The Social Media Life of Small Urban Spaces

The Social Media Life of Small Urban Spaces: Using Geotagged Twitter Data to Understand Urban Park Usage

Meghan Hade May 2014

The Social Media Life of Small Urban Spaces: Using Geotagged Twitter Data to Understand Urban Park Usage

A Planning Report Presented to The Faculty of the Department of Urban and Regional Planning

San JosĂŠ State University

In Partial Fulfillment of the Requirements for the Degree Master of Urban Planning

By Meghan Hade May 2014

Acknowledgements

I would like to express sincere appreciation to those who have made this project possible: My advisor, Richard Kos, for his enthusiastic and encouraging approach to teaching, for countless edits and revisions, and for introducing me to the world of geographic information systems. I am fortunate to have had an advisor and educator who is so invested in his students’ learning.

Stacy Bradley, and the San Francisco Recreation and Parks Department, for their support and involvement in this project.

Alan McConchie, and Stamen Design, for providing insight on their projects involving social media data.

Eric Fischer, for the inspiration and information he provided to this research.

My family: my Mom and Dad, for their unfaltering love and support, and for staunchley believing I could tackle any challenge. My brother Corey, for being such a wonderful sounding board as I worked through the ideas for this project, and for all of our conversations about cities and technology.

Thank you all for the part you played in this project.

Meghan Hade San Francisco, 2014

TABLE OF CONTENTS List of Tables and Figures...................................................................................... b Chapter 1: Introduction to Research Question and Literature Review.................... 1 Identifying challenges associated with urban space design and understanding how urban parks are used........................................................................................................................................ 3 Qualities of successful public space design................................................................................... 8 Guidelines for creating public spaces that fit with San Francisco’s cultural identity.......................... 9

Chapter 2: the History of Open Space Policy in San Francisco.............................. 11 Open space policy in San Francisco and the need to understand how parks are used.

Section 295...................................................................................................................................

The ’87 Memo...............................................................................................................................

The ’89 Memo...............................................................................................................................

Current process for determining shadow impact on park properties..............................................

12 13 14 16 16

Chapter 3: Overview of Case Study Site............................................................... 19 Union Square Park, San Francisco, California................................................................................ 20

Chapter 4: The 706 Mission Development Project Proposal.................................. 33 Potential shadow on Union Square cast by the project.............................................................. 35

Chapter 5: A New Way to Understand Park Usage............................................... 43 Twitter: a potential data source for urban planners and designers.............................................. 44 Methods for collecting geotagged tweets: an interview with Eric Fischer.................................... 49 Using geotagged tweets to understand park usage................................................................. 54

Chapter 6: A Modern Technique for a Classic Inquiry............................................ 59 Works Cited.......................................................................................................... 65 Appendix 1: San Francisco Planning Code Section 295........................................ 68 Appendix 2: Planning Observation Study of Union Square.................................... 69 Appendix 3: Munging Process for Twitter Data...................................................... 75 Appendix 4: D3 Script for Generating Union Square Twitter Data Scatterplot........ 83

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LIST OF FIGURES 1. San Francisco Proposition K, 1985.............................................................................13 2. Union Square, San Francisco...................................................................…………….19 3. President Roosevelt dedicates the Dewey Monument, 1903......................................21 4. San Francisco earthquake of 1906.............................................................................22 5. Homeless among ruins of former wealth, crude shelters in Union Square, 1906.........23 6. The City of Paris department store on Union Square after reconstruction, 1909.....23 7. Union Square from the St. Francis Hotel, 1968...........................................................24 8. Union Square, April 2010............................................................................................26 9. Site plan for Union Square...........................................................................................26 10. The southwestern corner of Union Square..................................................................27 11. Ice skating at Union Square, December 2010.............................................................28 12. Downtown Land Use and Density Plan.......................................................................29 13. Population density in San Francisco by census tract, in people per acre...................30 14. Major Open Spaces.....................................................................................................31 15. 706 Mission project proposal location.........................................................................34 16. The maximum shadow would occur on October 18th.................................................37 17. Planning Department observation study data for Union Square...................................39 18. Adult use of social networking sites and Twitter...........................................................46 19. 18 percent of all adult Internet users actively use Twitter, and use is evenly distributed among socio-economic backgrounds.........................................................................47 20. The Geotaggers’ World Atlas #4: San Francisco.........................................................50 21. Locals and Tourists #3 : San Francisco.......................................................................52 22. Demonstrating the density of geotagged tweet locations in Union Square...................55 23. Data visualization expanded to reveal trends over entire period of data.......................56 24. Data compressed to reveal trends on a 24-hour time scale.........................................57 25. Tweets grouped by the hour of day they occurred.......................................................57 26. San Francisco Planning Code Section 295.................................................................68

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Chapter 1: Introduction to Research Question and Literature Review

The Need for Urban Open Spaces

CHAPTER ONE Introduction to Research Question and Literature Review

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How might geotagged social media data be analyzed to better understand urban park usage, in particular Union Square plaza in San Francisco, California? This research question is important because there are such a wide variety of factors that need to be considered in the design and management of urban spaces, and in the policy planning for such places.

A nuanced understanding of how a park is used would allow planners, designers and policymakers to make improvements that would increase the use of the space, which in turn can increase the safety of the area. 1 2 Responding to changing visitor needs creates a more lively and engaging space,3 avoiding the creation of a “dead space.”4 A thoughtfully designed and managed space will also consider the needs of a wide variety of potential visitors, which will help with challenges of equity and accessibility in the space.5 This report will first review the ways design can invite or alienate people or types of uses, and the reasons why it is important to activate urban spaces and invite use by all people. Then, the report will look at why it is important to understand how a public space is used, using the shadow policy of San Francisco, and its application to Union Square Park, as a case study. An interview with a planner for the San Francisco Recreation and Parks Department will help illustrate the need for park usage data.

Next, we use this case study to test whether social media data from Twitter could be used to understand usage trends of the park. Methods for collecting this data will be discussed. Finally, the report will review the benefits and limitations of this approach, and review the real-world application of this approach already undertaken by a California open space organization.

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Seaman, P J. "It's Not Just About the Park, It's About Integration Too: Why People Choose to Use or Not Use Urban Greenspaces." The International Journal of Behavioral Nutrition and Physical Activity 7, no. 1 (2010): 78; Gehl, Jan. Life between Buildings: Using Public Space. Translated by Jo Koch. 6th ed. (Washington, DC: Island Press. 2011).

2 Jacobs, Jane. The Death and Life of Great American Cities. (New York: Vintage, 1992).

3 Cooper Marcus, Clare, Clare Miller Watsky, Elliot Insley, and Carolyn Francis, “Neighborhood Parks,” in People Places, 2nd edition, ed. Clare Cooper Marcus (New York: Van Nostrand Reinhold, 1998), 85-148.

4 Cranz, Galen. “The Sociology of Public Space.” Design Quarterly 129 (1985): 22-24.

5 Day, Kristen. “The Ethic of Care and Women’s Experiences of Public Space.” Journal of Environmental Psychology 20 (2000): 103-124; Malone, Karen. “Street Life: Youth, Culture and Competing Uses of Public Spaces.” Environment and Urbanization 14, no. 2 (2002): 157-168; Davis, Mike. “Fortress Los Angeles: The Militarization of Urban Space,” in Variations on a Theme Park : the New American City and the End of Public Space, ed. M. Sorkin (New York: Hill & Wang, 1992), 154-180; Iwarsson, S. and A. Stahl. “Accessibility, Usability and Universal Design--Positioning and Definition of Concepts Describing Person-Environment Relationships.” Disability and Rehabilitation 25, no. 2 (2003): 57-66.

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Identifying Challenges Associated with Urban Space Design and Understanding How Urban Parks are Used In order to explore the reasons for the selection of the research topic, it is helpful to understand the important role that design choices play in shaping urban spaces. The choices designers make can influence not only how a space is used, but also who feels comfortable using it, and, conversely, who may feel unwelcome. Understanding the ramifications of design choices and understanding how a space is used are mutually beneficial, and can be used in tandem to create new, or improve existing public spaces.

Two challenges associated with open space design: Equity and Accessibility The common goal for any public space is, ostensibly, to create a space for use by people, and one that both welcomes and attracts public use. According to Jan Gehl, a Danish architect and one of the current thought leaders on the topic of public spaces, social activity is key to the success of public spaces, because people are attracted to places where other people are, and where diverse activities occur. Public spaces can either invite or repel social activities (social activities can include engaging in an activity with an acquaintance, but it also can include engaging in a solo activity in a public realm), and designing spaces that isolate activities or exclude certain populations will not be as attractive to people, and will thus be used less.6 In the foundations of urban design theory, there is a history of tension between the designer/expert and the actual public users of the spaces.7 Frederick Law Olmsted, a historical figure in urban design who is considered one of the fathers of modern landscape architecture, discussed ways in which to provide city populations with relief from the urban environment.8 Olmsted envisioned parks as a place in which many uses can occur without interrupting one another, but he also warned that parks should not be designed only for current uses, but also for future, unimagined uses.9 As the design process necessitates navigating these decisions regarding the foreseen and unforeseen 6

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Gehl, Jan. Life between Buildings: Using Public Space. Translated by Jo Koch. 6th ed. Washington, DC: Island Press. 2011.

Olmsted, Frederick Law. Public Parks and the Enlargement of Towns. Cambridge: Riverside Press. 1902.

Ibid.

Ibid.

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uses for a space, urban designers play an active role in increasing or inhibiting social justice through design choices that affect possible uses and users.10 Thus, the urban designer is a mediator between legal and public pressures during the design process.11 However, urban designers can be exclusionary in their designs; for example, by only working to design spaces for certain populations, or only working to design spaces based on aesthetic appeal.12 Olmsted argues that, with regard to the design of public spaces, the work of urban designers should be measured “in the right to access, enjoy and participate in urban life.”13 However, public spaces do often inadvertently exclude, if not blatantly prohibit, certain uses within the space, and through the exclusion of uses, public spaces often exclude certain populations from use of the space.

A case in point: because their use of public space is often seen as illegitimate, the homeless are a group who are often excluded from public space use.14 This can be by design, such as the implementation of tilting bus stop seats that prevent a person from lying on them, or through lack of consideration for their needs (such as somewhere to place the larger belongings they may be carrying, power outlets to charge their phones, or free wireless internet access) during the design process.

Youths are another population group that tends to be excluded from full use of public spaces.15 When child labor and education laws were enacted, children were no longer working, contributing citizens, and their presence in the public realm was viewed as unacceptable, as this would mean they were not in school where they belonged.16 Thus, because unaccompanied children were no longer considered an acceptable user group, the design of public spaces began to ignore their needs (for example, the height of

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Van Deusen Jr., R. “Public Space as Class Warfare.” GeoJournal 58 (2002): 149-158.

Ibid.

Ibid.

Ibid.

Cooper Marcus, Clare, Carolyn Francis and Rob Russell, “Urban Plazas,” in People Places, 2nd edition, ed.

Clare Cooper Marcus (New York: Van Nostrand Reinhold, 1998), 13-84; Mitchell, Don. “The End of Public Space? People’s Park, Definition of the Public, and Democracy.” Annals of the Association of American Geographers 85(1) (1995): 108-133; Stevens, Quentin. "'Broken Public Spaces in Theory and in Practice."

Town Planning Review 80, no. 4 (2009): 371-392.

Malone, Karen. “Street Life: Youth, Culture and Competing Uses of Public Spaces.” Environment and Urbanization 14(2) (2002): 157-168; Simpson, Brian. “Towards the Participation of Children and Young People in Urban Planning and Design.” Urban Studies 34(5-6) (1997): 907-925.

Simpson, Brian. “Towards the Participation of Children and Young People in Urban Planning and Design.”

Urban Studies 34(5-6) (1997): 907-925.

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drinking fountains and pay phones in public spaces preclude use by unaccompanied children).17 In addition to being viewed as inappropriate during school hours, the presence of youth in public space can be perceived as dangerous.18 The broader public often misunderstands youth culture, and this leads to fear of the misunderstood (i.e., nonmainstream) activities, such as skateboarding or graffiti wall art, as well as fear that the youths cannot manage their own safety within the public realm.19 This fear can affect the determined acceptable use of public spaces for youths, and these fears have led to curfews and move-on laws, which exclude youths from public spaces. 20 21 A common method for confronting the problem of youth exclusion from public spaces is to create youth-specific spaces, such as skate parks. However, such places do not solve this problem. By segregating their realms of use, children are “rendered ‘invisible’,” because such spaces remove youth from the public realm, and place them in an isolated location. 22 This can be detrimental to their well being and development because it removes them from the safety of a populated area, and hinders the emotional development that youth experience through social interaction with a wide range of ages in the public realm, as compared to limited social interaction with their own peers.23 As discussed earlier, public spaces by design often prohibit certain uses within the space. This exclusion can be explicit or implicit, and can evolve in a number of ways.

One way that this can happen is as a result of poorly predicting the actual potential uses for a space. One example of this is the skyway system in St. Paul, Minnesota, a network of elevated, enclosed pedestrian connections between buildings throughout the downtown area. They were designed to create a comfortable downtown pedestrian walking zone by providing protection from the extreme Minnesota winter conditions, and 17 18

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Ibid.

Seaman, P J. "It's Not Just About the Park, It's About Integration Too: Why People Choose to Use or Not Use Urban Green spaces." The International Journal of Behavioral Nutrition and Physical Activity 7(1) (2010): 78; Stevens, Quentin. "'Broken Public Spaces in Theory and in Practice." Town Planning Review 80, no. 4 (2009): 371-392.

Malone, Karen. “Street Life: Youth, Culture and Competing Uses of Public Spaces.” Environment and Urbanization 14(2) (2002): 157-168.

Ibid.

Ibid.

Ibid.

Malone, Karen. “Street Life: Youth, Culture and Competing Uses of Public Spaces.” Environment and Urbanization 14(2) (2002): 157-168.

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providing a way to navigate the downtown businesses and shops without confronting unpleasant realities such as homelessness. Designed during a time of suburban flight, the skyways were once viewed as a way to attract people who had fled to the suburbs back to the urban core, and consumers away from suburban malls. 24 25 However, it later became clear that the skyways were detrimental to the commercial viability of the urban center because they removed nearly all pedestrian traffic from street level and, as a result, all vitality from the street.26 Creating such a space aimed at controlled uses lead to a “dead” space, a space that failed to attract activity.

The prohibition of certain uses from public spaces can also evolve as a result of governmental or corporate desire for social control. The design of urban spaces can be used to maintain social control, through both the physical materiality of the space as well as the psychological effects of the space.27 For example, Davis explains how security and safety have been prioritized in the design of public spaces in Los Angeles.28 Activities in such places are monitored for “safety”, which precludes the use of the spaces by certain populations viewed as dangerous, such as homeless and youths. Davis describes how, in what he calls “the end of what might be called the Olmstedian vision of public space in America,” middle- and upper-class individuals feel free to use public spaces in lowerclass Latino neighborhoods, while lower-class individuals do not feel free to use the “militarized” public spaces in upper-class neighborhoods (places that are heavily reinforced with security measures, such as financial districts).29 These militarized public spaces use design cues such as elevated walkways, reflective privacy glass and ramparts, to “warn off” lower-class individuals, who are able to read the design as unwelcoming.30 Schmidt concurs that design elements can send a message of how a

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Mendez, Michael. “Latino New Urbanism: Building on Cultural Preferences.” Opolis 1(1) (2005): 33-48.

25 Cranz, Galen. “The Sociology of Public Space.” Design Quarterly 129 (1985): 22-24.

26 Loukaitou-Sideris, Anastasia and Tridib Banerjee. Urban Design Downtown: Poetics and Politics of Form. Berkeley: The University of California Press. 1998.

27 Davis, Mike. “Fortress Los Angeles: The Militarization of Urban Space,” in Variations on a Theme Park : the New American City and the End of Public Space, ed. M. Sorkin (New York: Hill & Wang, 1992), 154-180.

28 Ibid.

29 Davis, Mike. “Fortress Los Angeles: The Militarization of Urban Space,” in Variations on a Theme Park: the New American City and the End of Public Space, ed. M. Sorkin (New York: Hill & Wang, 1992), 154-180.

30 Ibid.

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site should be used, and adds that although visually accessible, corporate open spaces (he uses this term where Davis uses the term “militarized”) are highly controlled.31 Urban designers clearly play an active role in increasing or prohibiting equality in accessibility through design choices that affect possible uses and users.32 With the differing needs of socio-economic groups (age groups, cultural groups, etc.), all user needs must be considered in public space design.33 Public spaces can be designed to accommodate the desired uses of all segments of the public, as well as address the range of users of the space.34 Iwarsson and Stahl studied the language used during the design process and found that there are three key terms that are used to describe meeting a range of user needs: accessibility, usability and universal design.35 Although planners and designers most commonly use the term “accessibility” when describing issues of equity in use of a public space, Iwarsson and Stahl claim that this term is associated with disability, whereas usability and universal design connote serving a broader population. Universal design is the widest-reaching concept, describing the method of designing not for individual user groups, but rather for a whole population with a continuum of needs and abilities.36 However, according to Loukaitou-Sideris and Banerjee, it may not be possible for one space to meet the needs of all conceivable users.37 They claim that a decline in the amount of public space and increased diversity in cities has led to increased isolation of groups with specific needs (“clubs”).38 This “specialization” of spaces contrasts with Olmsted’s view of public spaces, where people would use public spaces to mingle with those different from themselves.39 31

Schmidt, S. "World Wide Plaza: The Corporatization of Urban Public Space." Technology and Society Magazine, IEEE 23, no. 3 (2004): 17-18.

32 Van Deusen Jr., R. “Public Space as Class Warfare.” GeoJournal 58 (2002): 149-158.

33 Cooper Marcus, Clare, Clare Miller Watsky, Elliot Insley, and Carolyn Francis, “Neighborhood Parks,” in People Places, 2nd edition, ed. Clare Cooper Marcus (New York: Van Nostrand Reinhold, 1998), 85-148.

34 Iwarsson, S. and A. Stahl. “Accessibility, Usability and Universal Design--Positioning and Definition of Concepts Describing Person-Environment Relationships.” Disability and Rehabilitation 25(2) (2003): 57-66.

35 Ibid.

36 Ibid.

37 Loukaitou-Sideris, Anastasia and Tridib Banerjee. Urban Design Downtown: Poetics and Politics of Form. Berkeley: The University of California Press. 1998.

38 Ibid.

39 Loukaitou-Sideris, Anastasia and Tridib Banerjee. Urban Design Downtown: Poetics and Politics of Form. Berkeley: The University of California Press. 1998; Olmsted, Frederick Law. Public Parks and the Enlargement of Towns. Cambridge: Riverside Press. 1902.

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Qualities of successful public space design William Whyte, author of The Social Life of Small Urban Spaces, is considered to be one of the foundational experts on social activity in urban spaces.40 Whyte’s observational study of public plazas in New York found that the best-used spaces are sociable places, those that encourage social interaction.41 He also found that providing seating is crucial to attracting people and creating vibrancy, and movable seating is the most favorable.42 Mehta’s study of social interactions occurring in public space concurs, stating that urban spaces that offer a variety of seating options are livelier.43 Whyte’s study also found that shadows in an urban plaza do not control where people sit. However, a study specific to San Francisco by Zacharias, et al. found that, due to unique microclimatic conditions that exist throughout the city, sunlight did often affect how people chose to use plazas.44 Whyte also recommends the presence of a food vendor at a plaza, as this can attract people to a site.45 A 2012 study by Lamorena examining the use of parklets in San Francisco found that the primary activity observed in the parklets was eating and drinking.46 Another noted expert on social activity in public spaces is Ray Oldenburg, author of The Great Good Place. Oldenburg coined the term “third place,” describing places that are neither home (the first place) nor work (the second place).47 While people often think of coffee shops when thinking of third places, Oldenburg’s definition of this type of place is not limited to commercial environments; third places can include public plazas.48 40

Mehta, Vikas. "Look Closely and You Will See, Listen Carefully and You Will Hear: Urban Design and Social Interaction on Streets." Journal of Urban Design 14, no. 1 (2009): 29-64.

41 Whyte, William H. The Social Life of Small Urban Spaces. New York: The Project for Public Spaces. 1980.

42 Ibid.

43 *Mehta, Vikas. "Look Closely and You Will See, Listen Carefully and You Will Hear: Urban Design and Social Interaction on Streets." Journal of Urban Design 14, no. 1 (2009): 29-64.

44 Whyte, William H. The Social Life of Small Urban Spaces. New York: The Project for Public Spaces. 1980; Zacharias, John, Ted Stathopoulos, and Hanqing Wu. "Spatial Behavior in San Francisco’s Plazas: The Effects of Microclimate, Other People, and Environmental Design."

Environment and Behavior 36, no. 5 (2004): 638-658.

45 Whyte, William H. The Social Life of Small Urban Spaces. New York: The Project for Public Spaces. 1980.

46 Lamorena, Christine. “Parklets for the People.” Masters project, San Jose State University, May 2012.

47 Oldenburg, Ray. The Great Good Place. Cambridge: Da Capo Press. 1999.

48 Ibid.

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Oldenburg maintained that third places benefit society because this type of place is a "leveler,” a place where people can interact freely regardless of social status.49 He describes successful (i.e. popular and beloved) third places as visually plain (i.e. unprogrammed), having a playful mood, and providing a "home away from home."50 An article by Crain also discusses “third places,” with regard to how they are managed.

He claims that public space success is created through continued management (which includes maintenance and adapting the space to changing needs), not just through the mere creation of spaces in and of themselves.51 Privately-owned third places are forced to recognize this or they will go out of business, but public “third places” often are unsuccessful because they do not receive such attention to maintenance and “market” desires.52 Rather than relegating the management of public spaces to a government department, Crain believes that involving the community in the design process creates a sense of ownership of the place, which can aid in better management (i.e. maintenance and adaptation) of the place.53 Guidelines for creating public spaces that fit with San Francisco’s cultural identity The San Francisco Planning Department updated the San Francisco General Plan’s Recreation & Open Space Element in 2011. This Element outlines goals and policies for open space in San Francisco, including long-term goals for the next one hundred years. At the time of the Element update, there were 3,433 acres of open space in the city, and 560 of these were non-traditional open spaces, including linear spaces and privately owned public accessible open spaces.54 The Element outlines the guiding principles the city will follow in maintaining current open spaces and developing new ones. These principles include creating “integrated and multifunctional” spaces, creating a “sense of place” in city open spaces, and striving for “equity and accessibility” in the design and programming of these spaces.55 In explaining why 49

Ibid.

Ibid.

51 Crain, Brendan. “Get Out of the Way.” Shelterforce, February 2013, http://www.shelterforce.org/article/3058/get_out_of_the_way/ (accessed March 20, 2013).

52 Ibid.

53 Ibid.

54 San Francisco Planning Department. Recreation & Open Space Element: Revised Draft. San Francisco, 2011.

55 Ibid.

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creating a sense of place is important, the Element describes San Francisco’s position as a cultural center of the Bay Area region, and states that the open spaces in the city should reflect the city’s cultural qualities as well as natural qualities.

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CHAPTER TWO The History of Open Space Policy in San Francisco 11

Open Space Policy in San Francisco and the Need to Understand How Parks are Used In this section, the history of shadow legislation in San Francisco will be examined.

This will be useful for later stages of this research because it provides an impetus for park usage studies; today, permitting a new building to cast shadow on a park is contingent upon proving that the new shadow will not negatively affect the use of the park. To determine this, city staff must understand the current use of the park, an analysis that could be aided by geotagged social media data.

Proposition K: The Sunlight Ordinance In June of 1984, San Francisco voted on a proposition that would have a lasting impact on the approval process for development in their city. This proposition, known as “Prop K: Park Shadow Ban,” did not need to go through the regular legislative process due to a provision in the City Charter that allows ordinances to be placed on the ballot if it is signed by four or more City Supervisors. Prop K proposed new regulations on the construction of tall buildings in San Francisco; if passed, the City Planning Commission could not approve any project that proposed a building height of over forty feet if it cast significant shadow on existing and planned recreational areas. Before Prop K went to ballot, the City Planning Commission would use discretion towards permitting new projects that would shade parks, but no formal standards existed. The new ordinance sought to introduce formal shadow limits to guarantee enjoyable open spaces for future generations, but it also played to San Francisco’s long-standing preservationist ethos, which restricts building and limits density in the name of protecting the city’s unique character.

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Prop K: Park Shadow Ban “The Proposal: Proposition K says the City Planning Commission may not approve any building project which causes significant shading of recreational areas like parks and playgrounds. Exceptions would include certain projects in progress, buildings less than 40 feet high, buildings constructed for recreation or park-related purposes, or building which only cause shade during the first hour after sunrise and/or the last hour before sunset. Also, any building already constructed when this ordinance goes into effect could be rebuilt to the same height in the same location, if the need arises.”1 Figure 2. San Francisco Proposition K, 1985

Section 295 Prop K passed and on January 31st, 1985 was approved and codified as Section 295 of the San Francisco Planning Code, titled “295, Height Restrictions on Structures Shadowing Property Under the Jurisdiction of the Recreation and Park Commission.”56 Section 295 expounded on the initial phrasing of Prop K, refining “recreational areas like parks and playgrounds” to “property under the jurisdiction of the Recreation and Park Commission,” and providing further detail for how the ordinance would apply to projects for which building permits had been filed prior to the passing of Prop K. As with Prop K, Section 295 stated that the ordinance would not apply to buildings under forty feet in height, structures that would shade park land only during the first hour after sunrise and/or the last hour before sunset, structures to be constructed on park land by the Recreation and Parks Department, or structures the same height as, or shorter than, the structure existing when Prop K passed.

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The City and County of San Francisco. San Francisco Planning Code. http://www.amlegal.com/nxt/gateway.dll/California/planning/article25heightandbulkdistricts?f=templates$fn =default.htm$3.0$vid=amlegal:sanfrancisco_ca$anc=JD_295 (accessed April 15, 2014).

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If a building failed to meet any of this provisions (i.e. if it was taller than forty feet, and if it cast shadow after the first hour after sunrise or before the last hour before sunset), the permit for the building would then be contingent upon an approval by the Recreation and Park Commission and the Planning Commission. The Recreation and Park Commission’s responsibility would be to determine that the new shadow cast by the proposed project would be insignificant, and that it would not adversely impact the use of the park to be affected by the shadow.

The guidelines provided by Section 295 specified that the Planning Commission and the Recreation and Park Commission were to meet at a later date to adopt language explaining the criteria for the provisions in this Section. The outcome of this meeting, and the criteria adopted by the two commissions, would become known as the “’87 memo.”

The ’87 Memo On October 22, 1987, the San Francisco Planning Department issued a memorandum to the Planning Commission and Recreation and Park Commission.

Since Section 295 required the joint adoption of criteria for determining the impact of a potential shadow, this memo outlined methodology used in determining the significance of shadow impacts and the technical methods used for shadow prediction. This memo also included an analysis of 15 downtown parks that could potentially be shadowed by new development, using methodology developed through a professional partnership between the Planning Department and the University of California-Berkeley, and provided general criteria for determining shadow impact acceptability beyond these fifteen parks.

The ’87 Memo begins this analysis by defining the terms and units of analysis for calculating shadow impact. The basic unit of analysis is the foot-hour, which is the amount of light or shadow that hits one square foot for one hour. The amount of sunlight that hits a square foot for one hour is called a “sun foot-hour,” and the amount of shadow is called a “shadow foot-hour” (sfh).

A park’s Total Annually Available Sunlight (TAAS) is the square footage of the park times 3,721 hours, the number of hours each year between one hour after sunrise and one hour before sunset (the hours of concern for Section 295). The TAAS does

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not account for existing buildings, trees, or other sources of shadow. For example, a 1,000 square foot park would have 37,210,000 foot-hours of TAAS. The memo proposed to establish an absolute limit for shadow that falls upon each park. Using a computer modeling system, the current total existing sfh for each park could be established, which could be then compared to the TAAS to see what percentage of TAAS was already shaded. With the establishment of an absolute limit, or a quantitative cap on the amount of allowable sfh for each park, new projects that proposed to cast shadow on a park would need to “withdraw” from this established shadow “budget,” if any sfh are available for that park.

The memo acknowledges that each shadow will have unique characteristics, and that each park may be uniquely affected by a new shadow. It therefore proposed that a set of qualitative criteria be used in conjunction with qualitative criteria to determine the significance of the proposed shadow’s impact on the use of the park. The qualitative criteria fall into three categories: value of the sunlight, shadow characteristics, and building characteristics.

The “value of sunlight” criteria address the quality of sunlight that would be blocked by a potential shadow. This category requires analysis of the time of day and time of year of the shadow. The value of the time of the shadow will be unique to each park, as each park varies in the time of day and the time of year that it is most frequently visited, and because the ways the park is used may vary throughout the day or throughout the year. The memo gives the example that a downtown park’s most valuable sunlight may be the midday hours, when people visit during their lunch breaks, but a neighborhood playground’s most valuable sunlight may be in the afternoon hours, when children visit to play after school.

The “shadow characteristics” criteria concern the size, duration and location of the shadow, all of which would need to be considered on a case-by-case basis with regard to the park that would be affected. The memo states that small shadows would be preferred to large, unless the shadow has a long duration, or occurs over an area of the park where the amount of sunlight impacts the use for that area. The memo also urges decision-makers to consider not only the existing use of the park,

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but also potential future uses, when evaluating the impact of these shadow characteristics.

The “building characteristics” category addresses the need to evaluate the public good that would be served by the proposed project. The memo states that projects “in the public interest in terms of a needed use or building design and urban form may be allocated a larger portion of the Absolute Limit than other buildings.”57 The ’89 Memo Two years later, on February 3, 1989, the Planning Department and the Recreation and Parks Department wrote a joint memo to the Planning Commission and the Recreation and Park Commission. This memo, known as the “’89 memo,” prescribes a two-step process for determining significance of shadow: first, set an Absolute Cumulative Limit for new shadow allowed in each park, and second, evaluate individual building impacts according to qualitative criteria in ’87 memo.

The Absolute Cumulative Limit (ACL) is the maximum allowable additional sfh expressed as a percentage of the total foot-hours for each park over a period of one year (as determined using the computer modeling system developed for the Planning Department by the University of California-Berkeley). The memo outlined the two key factors that determine the impact a shadow will have on a park: the size of the park and the amount of existing shadow on the park. Based on these two factors, it was recommended that parks under two acres in size that were already shaded 20 percent or more per year be prevented from acquiring any additional shadow. For these parks, an ACL of zero should be adopted. For parks over two acres in size that are in shadow 20-40 percent of the year, an ACL of 0.1 percent was recommended. For parks shadowed less than 20 percent of the year, it was recommended that additional shadow up to 1.0 percent could be permitted Current Process for Determining Shadow Impact on Park Properties Today, the process for approving additional shadow on a San Francisco park relies upon the qualitative and quantitative criteria established in Section 295, the ’87 57

San Francisco Department of City Planning. "Re: Proposition K--The Sunlight Ordinance." Memorandum, San Francisco, 1987.

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memo, and the ’89 memo. Applicants of all projects exceeding 40’ in height file a Shadow Study Application with the Planning Department, and Planning staff prepare a shadow fan (a rough spatial projection used to estimate the extent of shadow that could be cast by the proposed project) to determine whether the shadow could potentially land on a property under the jurisdiction of the Recreation and Parks Department. If the shadow fan suggests that park shadowing is a possibility, the project sponsor is responsible for commissioning a detailed shadow analysis to be completed by an independent environmental consultant.

The consultant provides the Recreation and Parks Department (RPD) Capital and Planning Division with a shadow analysis report, detailing the nature of the shadow: its size, duration, daily and annual times of appearance and disappearance, and maps visualizing the location of the shadow throughout its duration.

RPD staff planners then evaluate the shadow report, first to determine that the amount of shadow falls within an acceptable range for the affected park. If the total amount of shadow on the park will be under the ACL after the new shadow amount is added, it is considered to be quantitatively acceptable. Next, the planners consider the report findings with regard to qualitative criteria: the time of day and time of year the shadow occurs, the size and duration of the shadow, the location of the shadow, and the public benefit to be provided by the proposed project. The planners analyze this qualitative data with regard to their knowledge of the park, supplemented with additional site visits, discussions with the Park Area Manager covering the area in which the particular park is located, and geographic information systems (GIS) data. The GIS data and site visits allow the planners to familiarize themselves with the park land use designations, but do not give a broadlevel understanding of the variation in the actual park use throughout the day or throughout the year.

The Park Area Managers have the most familiarity with the day-to-day and seasonal use of the park; they have a general idea of the ways people use the park, and how the uses vary throughout the day and year. This “on the ground” knowledge of the park operations gives the planners information to consider with regard to the daily and annual times of the shadow’s appearance at the park, and to the areas of the park that the proposed project would shadow. The Park Area Manager’s 17

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knowledge is valuable, though it is anecdotal and does not provide the planners with quantitative park usage data they can cite in their findings report. While the Recreation and Parks Department does conduct surveys to gather information on their recreational programming, they do not do park user counts or any sort of usage tracking that could provide this type of quantitative data on non-programmed activity.

The planners then prepare a staff report for the Recreation and Park Commission with their findings. If they find that the potential shadow will not be significant and that it will not adversely impact the use of the park, then they recommend that the Commission approve the additional shadow on the park. The Commission hears the Recreation and Park Department's recommendation, then hears comment from the project sponsor as well as the public on the item. If the Commission approves the additional shadow, the project then moves forward to the Planning Commission for their approval on their project application.

Clearly, it is important that the Recreation and Parks Department understand how their parks are used, so that they are able to determine whether a shadow will have a negative impact on the park it shades. This understanding is especially important for parks that are often the subject of such shadow reviews, in particular parks in the downtown area, where zoning allows tall building construction. One downtown park, Union Square Park, was recently the subject of this type of investigation, and usage data was needed for determining the shadow impact. In the next chapter, an overview of the history and design of Union Square Park will provide context for San Francisco’s shadow policy, and will demonstrate the need for a more comprehensive source for usage data.

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CHAPTER THREE

Overview of Case Study Site

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Union Square Park, San Francisco, California The History of Union Square Union Square, according to the San Francisco Parks Alliance, is one of the most historic and beloved places in San Francisco, and “each change it has undergone reflects the greater shifts in the history of our country.” 58 The park is located in downtown San Francisco, covering one city block bounded by Post Street, Stockton Street, Geary Street, and Powell Street. This 2.58-acre park, which is public land under the jurisdiction of the San Francisco Recreation and Parks Department, is today the center a vibrant eponymous shopping district, but this was not always the case.

Union Square was first designated as parkland in 1847, when Jasper O’Farrell, commissioned by the City of San Francisco to lay out a street plan for the city, chose this block to be one of two public squares.59 Later, Colonel John Geary, the first mayor and postmaster of the city, deeded Union Square to the city to be held in perpetuity as a park. 60 On the eve of the Civil War in 1861, the previously nameless park was deemed Union Square, as a demonstration of support for the Union. 61 Within the next twenty years, the surrounding neighborhood would become a residential district, with three churches facing the park. 62 In 1903, a 91-foot-tall column was erected at the center of the square that still exists today. Dedicated by President Roosevelt in that same year, it serves as a memorial for Admiral Dewey’s 1898 naval victory during the Spanish-American War. 63

58

San Francisco Parks Alliance. Union Square. www.sfparksalliance.org/visit/parks/union-square (accessed April 15, 2014).

59 Ibid.

60 Ibid.

61 Ibid.

62 Ibid.

63 Ibid.

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Figure 4: President Roosevelt dedicates the Dewey Monument, 1903. (Photographer unknown.)

The surrounding neighborhood began to shift from residential to commercial when the 1906 earthquake devastated San Francisco.64 The park became a place where displaced residents, whose homes had been destroyed by the earthquake, camped and congregated.

64

San Francisco Parks Alliance. Union Square. www.sfparksalliance.org/visit/parks/union-square (accessed April 15, 2014).

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Figure 5: San Francisco Earthquake of 1906: Stockton Street from Union Square looking toward Market Street, 1906. (Photograph by H.D. Chadwick.)

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Figure 6. Homeless among ruins of former wealth, crude shelters in Union Square, 1906.

(Photograph by Underwood & Underwood)

Figure 7. The City of Paris Department Store on Union Square after reconstruction, 1909.

(Today this is the Neiman Marcus Department Store.) (Photographer unknown.)

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It was not until the city began to recover from the disaster and rebuild that Union Square became the central shopping district it is today. As the neighborhood flourished, so did demand for parking.65 The Union Square Garage Corporation was formed to lobby for permission to build a parking structure under Union Square, which was to be the first underground parking structure in the world.66 Whether a private corporation could lease space under public land was a contentious issue, and the decision was elevated to the Supreme Court of California, who ultimately deemed it permissible.67 Construction for the underground parking structure, however, did not begin until 1941.68

Figure 8. Union Square from the St. Francis Hotel, 1968. (Photograph by Roger Wollstadt)

65

San Francisco Parks Alliance. Union Square. www.sfparksalliance.org/visit/parks/union-square (accessed April 15, 2014).

66 Ibid.

67 Ibid.

68 Ibid.

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Between the 1970s and the late 1990s, the square fell into disrepair. It had become a place frequented by homeless who would camp and sleep in the park.69 70 In 1997, the City announced a competition for a redesign of the park, with the winning design being the square that exists today. The redevelopment was completed in eighteen months, requiring $25 million in publicly and privately funded renovations, partially paid for by parking revenues. 71 72 The renovated park reopened on July 25, 2002, with a goal to improve access and keep the space active. 7374 The park’s design, drawing inspiration from a redesign of Bryant Park in Manhattan, which was based on William Whyte’s park usage studies, included moveable folding chairs for the use by park visitors.

69

Fagan, Kevin. "A Squaure is Born." SF Gate. San Francisco Chronicle. July 26, 2002. www.sfgate.com/bayarea/article/A-square-is-born-Face-lift-at-S-F-s-most-2818906.php (accessed April 15, 2014).

70 Epstein, Edward. "Remodel To Close Union Square / S.F.'s prime plaza to be prettied up." SF Gate. San Francisco Chronicle. December 27, 2000. http://www.sfgate.com/news/article/Remodel-To-Close-UnionSquare-S-F-s-prime-3302175.php (accessed April 15, 2014).

71 Fagan, Kevin. "A Squaure is Born." SF Gate. San Francisco Chronicle. July 26, 2002. www.sfgate.com/bayarea/article/A-square-is-born-Face-lift-at-S-F-s-most-2818906.php (accessed April 15, 2014).

72 Epstein, Edward. "Remodel To Close Union Square / S.F.'s prime plaza to be prettied up." SF Gate. San Francisco Chronicle. December 27, 2000. http://www.sfgate.com/news/article/Remodel-To-Close-UnionSquare-S-F-s-prime-3302175.php (accessed April 15, 2014).

73 Fagan, Kevin. "A Squaure is Born." SF Gate. San Francisco Chronicle. July 26, 2002. www.sfgate.com/bayarea/article/A-square-is-born-Face-lift-at-S-F-s-most-2818906.php (accessed April 15, 2014).

74 MJM Management Group. Union Square Park Case Study. mjmmg.com/union-square-park-case-study (accessed April 15, 2014).

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Existing conditions: the current design of Union Square

Figure 9. Union Square, April 2010. (Photograph by Tony Fischer Photography)

Figure 10. Site plan for Union Square. (San Francisco Recreation and Parks Department, 2014.)

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The redesigned square features an open, hardscaped plaza at the center, which covers the majority of the square, as shown in figures 9 and 10. The northern side of this hardscaped area features a performance stage, as well as tiered seating facing the center of the square. There are two cafes, one of the eastern edge of the plaza, and one on the western edge; both feature outdoor cafe seating facing the interior of the square. There is also an entertainment-ticketing kiosk on the western edge of the plaza. Â

Figure 11. The southwestern corner of Union Square. (Photograph by BrokenSphere)

Along the southern edge, the plaza grade steps down to meet the lower elevation of Geary Street. There are stairways for walking down to the street level interspersed with landscaped terraced steps, meant for sitting. There are tables and chairs along this edge as well. The center of the square, still anchored by the Dewey Monument, features table and chairs that can be moved and rearranged by park visitors.

The park is the third largest open space in downtown San Francisco.75 On a daily basis, tourists, residents, shoppers, and employees of local businesses are the primary park visitors, using it as a mid-block pass-through and for passive activities,

75

San Francisco Department of City Planning. "Re: Proposition K--The Sunlight Ordinance." Memorandum, San Francisco, 1987.

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such as eating lunch, taking photos, and sitting.76 Events are frequently held at the square. Throughout the week, smaller events pop up in the middle of the square, such as art sales where artists set up large easels to display their work.

Occasionally, the square is reserved for large events, such as the Nike Women’s Marathon, which brings over 25,000 runners to Union Square on a mid-October Saturday each year. Such large event organizers often set up large tents to cover the center of the hardscaped plaza area. During the winter holiday season, an outdoor skating rink and large Christmas tree attract many visitors to the square in the afternoons and evenings.

Figure 12. Ice skating at Union Square, December 2010. (Photograph by Laura Hamilton)

Opportunities and challenges in the surrounding area The neighborhood surrounding the square is also known as Union Square. The Union Square Business Improvement District (BID) is a special assessment district established by local property owners and business owners in 1999 with the stated intent of improving the conditions and economic vitality of the Union Square area.77 The San Francisco Planning Department includes Union Square in the “Downtown Area” for planning purposes. According to the Downtown Land Use and Density Plan from the Planning Department’s 2011 Land Use Index (figure 13), Union 76

Mauney-Brodek, Karen and Meghan Hade. "706 Mission Street, Evaluation of Shadow Impact on Union Square." Staff report, Capital and Planning Division, San Francisco Recreation and Parks Department, San Francisco, 2013.

77 Mjellem, Linda and Karin Flood Eklund. "Greater Union Square Business Improvement District Management Plan." Union Square Business Improvement District, 2009.

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Square Park is the center of the “Downtown Retail� area, surrounded by general commercial, downtown office, and mixed-use areas.

Union Square Park

Figure 13. Downtown Land Use and Density Plan. (San Francisco Planning Department. "Land Use Index" General Plan, the City and County of San Francisco.)

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The Downtown Area isArea oneisofone the of most populated areas areas in the in city.

The Downtown the densely most densely populated the city.

The Downtown AreaUS is Census one of the most densely populated in the city.that is According to 2010 data, the park situated in areas a Census tract According to 2010 US Census data, theispark is situated in a Census tract that is According to 2010 USalthough Census the data, the parkdensity is situated in tract a Census tract that is not highly populated, business in this leads to a much not highly populated, although the business density in this tract leads to a much not highly populated, although business density in thisnumber tract leads to a much higher daytime population thanthe the residential population reflected in higher daytime population than the residential population number reflected in higher daytime population than the residential population number reflected in of Census data.

The tracts immediately west of the park have the highest levels Census data. The tracts immediately west of the park have the highest levels of Census data.

The tracts west (see of thefigure park 14). have the highest levels of population density foundimmediately in SaninFrancisco population density found San Francisco (see figure 14). population density found in San Francisco (see figure 14).

Figure 14. Population Density in San Francisco by Census Tract, in people per acre. (Map by Figure 14. Population Density in San Francisco by Census Tract, in people per acre. (Map by author. Data source: US Census 2010) Data source: USinCensus 2010) by Census Tract, in people per acre. (Map by Figure author.

14. Population Density San Francisco author. Data source: US Census 2010)

The provision of open in thisindense downtown area isarea unevenly distributed.

The provision of space open space this dense downtown is unevenly distributed.

The provision of open space in this dense downtown area is unevenly distributed.

According to theto Major Open Open Spaces map for thefor Downtown Area (figure 15, 15, According the Major Spaces map the Downtown Area (figure According the2011 MajorLand Open Spaces map for the Downtown Area Union (figure Square 15, below)below) fromtothe the city surrounding from the 2011 Use LandIndex, Use Index, theblocks city blocks surrounding Union Square below) from the 2011toLand Use Index,access the citytoblocks surrounding Union Square Park are considered have open but the areas directly Park are considered to sufficient have sufficient access to space, open space, but the areas directly Park are considered to have sufficient access to open space, but the areas directly southeast and southwest of the of park deficient in open access.

Because southeast and southwest theare park are deficient in space open space access.

Because southeast and southwest of the park are deficient inhave open space access.

Because there are areas in such close proximity that do not sufficient open space, there are areas in such close proximity that do not have sufficient open space, there are areas in such close proximity that do not have sufficient open space, 30

30 30

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Union Square Park plays a crucial role in fulfilling the open space need in the Downtown Area.

Union Square Park

Figure 15. Major Open Spaces. (San Francisco Planning Department. "Land Use Index" General Plan, the City and County of San Francisco.)

It is important that close attention is paid to maintaining the quality of access to and enjoyment of the park, which is why any new potential shadow that may be cast on the park is given serious consideration under Section 295 by the Recreation and

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Parks Department and the Planning Department. In 2013, developers proposed to build a new tower on Mission Street, and the potential shadow cast by this project prompted a review of the potential impacts of shadow on Union Square.

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CHAPTER FOUR The 706 Mission Development Project Proposal 33

In 2013, the responsibility fell upon the San Francisco Recreation and Parks Department to determine whether the shadow cast by a new high-rise tower, to be built at 706 Mission Street, would have a negative effect on the way people used Union Square Park. Department planners used Section 295 guidelines, supplemented by anecdotal and observational evidence, to analyze the shadow’s impact.

Approximate distance: 800 feet

Figure 16 706 Mission project proposal location. (Source: Author)

On May 23, 2013 a special joint committee hearing was held with the San Francisco Recreation and Parks Commission and the San Francisco Planning Commission. The subject of the hearing was a proposed building project to be constructed at 706 Mission Street. The project sponsors originally proposed to rehabilitate the Aronson Building and add a new 520-foot tall adjacent tower,

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intended to house residential units and a new museum. 78 The joint committee hearing was “discussion and possible action by the Recreation and Park Commission to recommend to the Planning Commission that the net new shadow cast by the proposed project at 706 Mission Street on Union Square will not be adverse to the use of the park, as required by Planning Code Section 295 (the Sunlight Ordinance).” 79 The Recreation and Park Commission’s responsibility was to hear their staff present on the amount and nature of shadow that would be potentially cast by the proposed project, and make a determination as to whether the shadow would have a negative impact on the use of the park. Shortly before the joint committee meeting, however, the San Francisco Board of Supervisors had heard an appeal of the project Environmental Impact Report certification. Although the Board unanimously rejected the appeal and upheld the certification, the hearing did raise concern among the Supervisors about the amount of shadow that would be cast by the project, in particular on Union Square Park.80 As a result of the concerns raised during the Board of Supervisors meeting, the project sponsor proposed to reduce the height of the proposed new tower from 520 feet to 480 feet, which would result in a total maximum height of 510 feet after the addition of a mechanical penthouse. 81 Potential Shadow on Union Square Cast by the Project The reduction in tower height reduced the amount of potential shadow cast by the project by approximately 29 percent.82 According to the shadow analysis prepared by environmental consultants for the project sponsor, the proposed project, at its new reduced height, would cast 238,788 shadow-foot-hours (sfh) of shadow on

78

79 80

81 82

Mauney-Brodek, Karen and Meghan Hade. "706 Mission Street, Evaluation of Shadow Impact on Union Square." Staff report, Capital and Planning Division, San Francisco Recreation and Parks Department, San Francisco, 2013.

Ibid.

Bradley, Stacy. "706 Mission Street, Evaluation of Shadow Impact on Union Square: Staff Report Addendum and Amendments to Resolutions." Staff Report, Capital and Planning Division, San Francisco Recreation and Parks Department, San Francisco, 2013.

Ibid.

Ibid.

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Union Square annually, whereas the original design would have cast 337,774 sfh 83 Although this change represented a reduction in shadow from an amount equal to .09 percent of the theoretically available annual sunlight (TAAS) to .06 percent of the TAAS, the absolute cumulative limit (ACL) for the amount of allowable shadow for Union Square had already been reached. In fact, the ACL for Union Square had been raised only a year earlier, to allow for the development of the Transbay Terminal tower, which would cast shadow on Union Square beyond the approvable amount.84 To approve the shadow cast by the 706 Mission project, the ACL would need to be raised again, and this required a special joint meeting of the two commissions.

According to the Recreation and Parks Department’s Staff Report for the meeting, based on information from the shadow analysis, the proposed project would cast new shadow on Union Square during the morning during two periods annually: late fall (October 11th through November 8th), and late winter (February 2nd through March 2nd).85 The project would not cast new shadow on the park after 9:30 AM any day of the year.86 Figure 17 shows the shadow that would potentially be cast at 8:45 AM.

83

84

85 86

36

Bradley, Stacy. "706 Mission Street, Evaluation of Shadow Impact on Union Square: Staff Report Addendum and Amendments to Resolutions." Staff Report, Capital and Planning Division, San Francisco Recreation and Parks Department, San Francisco, 2013.

Mauney-Brodek, Karen and Meghan Hade. "706 Mission Street, Evaluation of Shadow Impact on Union Square." Staff report, Capital and Planning Division, San Francisco Recreation and Parks Department, San Francisco, 2013.

Ibid.

Ibid.

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Figure 17. The maximum shadow would occur on October 18th. At 8:45 AM the shadow would cover 87

approximately 17,715 square feet. (Diagram source: CADP Associates. "The 706 Mission Project Environmental Impact Report." 2013.)

The Planning Department provided the Recreation and Parks Department (RPD) planners with information about the current shadow conditions at Union Square. On an average daily basis, the park is sunny in the middle of the day, and shadowed during the early morning, late afternoon and early evening by existing buildings located east and south of the park.88 During the spring and fall, it is sunny from approximately 9:00 AM until 3:00 PM, and during the summer it is sunny from approximately 10:00 AM until 4:00 PM.89 During the winter, the amount of sun on union square is limited to the afternoon: from approximately 12:00 PM until 2:00

87

88 89

Mauney-Brodek, Karen and Meghan Hade. "706 Mission Street, Evaluation of Shadow Impact on Union Square." Staff report, Capital and Planning Division, San Francisco Recreation and Parks Department, San Francisco, 2013.

Ibid.

Ibid.

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PM.90 The park is shadowed by existing buildings during the hours outside of these time periods.91 The new shadow cast by the proposed 706 Mission project would cover pedestrian walkways, plaza spaces and seating areas in the park.92 To approve this new shadow, RPD planners needed to determine that it would not adversely impact the use of the park. According to the RPD Staff Report, during the morning hours when the new shadow would occur, Union Square is not heavily used, and is mainly used as a pass-through for residents and tourists.93 The Staff Report also states that the park is mainly used for “passive recreation,” which means that people use it primarily for leisure activities such as sitting, talking, taking photos and people watching, rather than active recreational activities such as playing and exercising.94 The RPD goes on to explain that the park observations have shown it is most heavily used during the mid-day: “the San Francisco Planning Department has previously conducted park usage observation studies of Union Square, which found that usage of Union Square was relatively light during the morning hours and that the primary use of the Square during this time was by people passing through.”95

90

91 92 93 94 95

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Mauney-Brodek, Karen and Meghan Hade. "706 Mission Street, Evaluation of Shadow Impact on Union Square." Staff report, Capital and Planning Division, San Francisco Recreation and Parks Department, San Francisco, 2013.

Ibid.

Ibid.

Ibid.

Ibid.

Ibid.

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Figure 18. Planning Department observation study data for Union Square. See appendix for full set. (Source: San Francisco Planning Department. "Transit Center District Plan Presentation Slides." August 2012.

The Planning Department’s observation study of Union Square was conducted on August 24th, 2012, as research for the Transit Center District Plan. The study noted the weather conditions and logged activity within the park every half hour between 7:00 AM and 9:30 AM. Figure 18 shows the way the Planning Department displayed the data they captured for each half-hour time increment and shows what use they observed from 8:30-9:00 AM. Although there were four types of use for which they were watching (exercise, play, sedentary, and taking photos), during this time they only recorded sedentary activity; the location of this activity is signified on the map by blue markers.

This observation study, used by RPD planners to help determine whether the new shadow cast by the 706 Mission project would adversely impact the use of the park, provides data for only one day, and for a summer day, whereas the new shadow would occur during several weeks of late winter and again during several

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weeks in late fall. The observation study does not provide a statistically relevant dataset, and it does not provide a clear understanding of how the use of the park varies throughout the day and throughout the year. A much larger dataset is needed, but neither the Planning Department nor the Recreation and Parks Department have the resources to conduct frequent in-person park user counts.

Stacy Bradley is the Planner for the San Francisco Recreation and Parks Department responsible for overseeing Section 295 shadow reviews. She earned her Master’s in Urban Planning degree with a concentration in environmental planning from Columbia University. While in school, she interned at UNOPS, an operational arm of the United Nations, where she created an intranet site for internal collaboration, as well as an animated data visualization of all of the UNOPS sites around the world.

Stacy has been working as a Planner for the Recreation and Parks Department since March of 2012; her work with the department has focused on citywide policy documents and departmental property acquisition. She has managed shadow review for five projects during this time: 706 Mission Street, 345 Brannan Street, 346 Potrero Avenue, 650 Indiana Street, and 190 Russ Street.

Soon after Stacy joined the department, the 706 Mission project was about to go before the Recreation and Parks Commission and the Planning Commission in the special joint hearing. She helped to organize the information to be presented to the Commissioners, and wrote an addendum to the staff report. Shortly before the joint hearing, the project sponsor, under pressure from the San Francisco Board of Supervisors, reduced the height of the project. This meant that the shadow analysis needed to be revised to account for the reduced height and the resulting reduction in shadow on Union Square. There was also a push to clarify within the Union Square shadow budget an increase in sunlight that had been the result of a Macy’s remodel years earlier. This remodel reduced the height of the Macy’s building directly across the street from the park, thus increasing the amount of sunlight on the park, but the cumulative shadow data for Union Square had never been adjusted to reflect this change. Making this adjustment was complicated by the fact that Section 295 does not account for a possible reduction in building height; it presumes development will preserve the status quo if they do not raise the heights.

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Stacy explained that none of the projects she has reviewed to date have constituted an adverse impact on the use of a park, but that she would consider a shadow that lasted a long time over a park, covering a large area, to be causing an adverse impact. She explained that each shadow is a unique case, though, because each determination depends on the use and projected use of the park in question. For example, children’s play areas within parks are especially sensitive to shadow, but in an area used as a sports field, a shadow could be either negative or positive.

To determine whether a shadow will adversely impact the use of a park, Stacy explained, her team first reviews the shadow impact report prepared by the consultant for the project sponsor. They aim to understand the overall impact on the park by understanding who uses the park, what shadow currently exists on the park, and how the park use may change in the future (for example, a parking lot that may not be currently impacted by shadow, but it may be an adverse impact if the parking lot was turned into a basketball court).

Stacy explained the ways in which the department currently understands how their parks are used. If any part of the park to be shaded is permitted or can be reserved, or if there is a clubhouse or recreation center, they can check with department operations staff, who can provide permitting, reservation and enrollment statistics. If there are no such park features, they rely on “anecdotal evidence� from the Park Managers and staff who are on the park all the time and understand the use.96 For a shadow review, they may do a park usage observation study, but the time of the review may not be the same time of year the shadow would occur. Shadow reviews are never a yearlong process, and it is very hard to time a study properly.

Even when they are notified a year in advance that a project will require shadow review, the shadow analysis is never prepared by the consultant far enough in advance to allow for observation study on all of the times and dates the shadow would occur.

96

Bradley, Stacy, interview by Meghan Hade. (March 6, 2014).

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Stacy believes that although the department has conducted observation studies in the past, further studies would benefit the department in many ways. They would not only help with shadow reviews, but they would help with programming current use, and, if an area were found to be under-used, the study would help capital planning for that park. The 2012 Planning Department observation study of Union Square helped significantly with the 706 Mission shadow review. According to Stacy, it showed that there was not a strong correlation between shadow and park use. The study confirmed that Union Square is a passive-use park and that people sit in the park in the sun and in the shade, that there is no connection between sun and use for this park. It helped the department conclude that there would be no adverse impact caused by the proposed project’s shadow.

Quantitative data for park usage would help the department get a better picture of usage for shadow reviews. It could also help operations by showing which parks are subject to heavier use and would require more frequent renovation and maintenance. It could also show which parks are under-used and would benefit from programmatic updates. Such data could be utilized by capital planning to analyze park usage based on the entire park system, and aid in planning where to focus bond money in the future.

One potential source for such quantitative data is publicly available location-based social media data, such as Twitter data.

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CHAPTER FIVE A New Way to Understand Park Usage

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In previous chapters, discussion of shadow policy in San Francisco demonstrated that legislation requires City staff to understand how their parks are used. Union Square Park and the 706 Mission project approval, which required an understanding of the use of Union Square, were discussed because they provided context for current park policy and an example of a recent application of shadow policy. The methods currently used by park planners to gather usage data were reviewed, revealing a need for a more comprehensive source for park usage data.

Next, we will examine Twitter data and its ability to meet this need.

Twitter: A potential data source for urban planners and designers Twitter is an online social network and microblogging site that allows people to post and read short messages in real-time via the web, text message, or smart phone application.97 These messages (tweets) are limited to 140 characters of text and can only be created by people who sign up for a Twitter account, but anyone can read them without registering. Most accounts are public, but users do have the option of a private profile, where only approved followers may read their Tweets.

Twitter has referred to itself as the “global town square,” because people can communicate without regard to their geographic location.98 Twitter started in 2006 and quickly gained a large user base of celebrities, international political leaders, protest organizers, news agencies, and ordinary people. By 2009, one billion tweets had been posted. Today Twitter has 241 million active users monthly posting an average of 500 million tweets per day.99 This amounts to 3.44 percent of the world’s population, and while 77 percent of the users reside outside of the United States, a reported 9.1 percent of the U.S. population tweets.100 101 102 The cultural significance of this Twitter activity is such that the Library of Congress maintains a historical archive of all Tweets. 103

97

TechCrunch. Twitter. www.crunchbase.com/company/twitter (accessed April 15, 2014).

The Brookings Institution Center for Technology Innovation. "The "Town Square" in the Social Media Era: A Conversation with Twitter CEO Dick Costolo." June 26, 2013. www.brookings.edu/events/2013/06/26-townsquare-social-media-twitter-costolo (accessed April 15, 2014).

99 Twitter. About. about.twitter.com/company (accessed April 15, 2014).

100 Ibid.

98

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The Pew Research Center, in their study of Internet usage, found that 72 percent of adults in the U.S. who use the Internet use social networking sites, up from 67 percent only a year earlier. When Pew first started researching social media networks in 2005, only 8 percent of adult Internet users were using social networking sites.104 As shown in Figure 19, Pew found in their 2013 study that 18 percent of online adults are Twitter users; a number they say has doubled since 2010.105 Figure 20 shows the socio-economic breakdown of the Twitter user base, which is fairly even distributed among gender, income and educational background.106 However, there is a large disparity between age groups, with people ages 18 to 29 making up the largest portion of users.107

101

102 103

Leetaru, Kalev, Wang, Shaowen, Cao, Guofeng, Padmanabhan, Anand, and Shook, Eric. "Mapping the global Twitter heartbeat: The geography of Twitter" First Monday [Online], Volume 18 Number 5 (22 April 2013) TechCrunch. Twitter. www.crunchbase.com/company/twitter (accessed April 15, 2014).

Leetaru, Kalev, Wang, Shaowen, Cao, Guofeng, Padmanabhan, Anand, and Shook, Eric. "Mapping the global Twitter heartbeat: The geography of Twitter" First Monday [Online], Volume 18 Number 5 (22

April 2013) 104

Brenner, Joanna and Aaron Smith. "72% of Online Adults are Social Networking Site Users." Pew Internet.

Pew Research Center. August 5, 2013.

105 Ibid.

106 Ibid.

107

Ibid.

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Figure 19. Adult use of social networking sites and Twitter. (Source: Joanna Brenner and Aaron Smith. "72% of Online Adults are Social Networking Site Users." Pew Internet. Pew Research Center. August 5, 2013.)

46

Figure 20. 18 percent of all adult Internet users actively use Twitter, and use is evenly distributed among socioeconomic backgrounds. (Source: Joanna Brenner, and Aaron Smith. "72% of Online Adults are Social Networking Site Users." Pew Internet. Pew Research Center. August 5, 2013.)

Location metadata attached to Tweets According to Twitter, 76 percent of active users are accessing their service via mobile device, and since 2009, Twitter users have had the option of enabling geolocation on their accounts.108 109 This means that their Tweets reveal information about the user’s location in one of two ways, typically. If the “Exact Location” is recorded in the Tweet’s metadata, a set of coordinates is listed (called a “geotag”),

108

Twitter. About. about.twitter.com/company (accessed April 15, 2014).

109

Leetaru, Kalev, Wang, Shaowen, Cao, Guofeng, Padmanabhan, Anand, AND Shook, Eric.

"Mapping the global Twitter heartbeat: The geography of Twitter" First Monday [Online], Volume 18 Number 5 (22 April 2013)

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which pinpoints a location using the global positioning system (GPS), wifi, or cellular triangulation.110 “Place� metadata is a city or neighborhood that the user selects from a list of location options in the software interface they use to submit the Tweet.111 While Twitter does not provide statistics on the number of users who opt-in to geolocation, a number of recent studies have gathered data and provide a range of statistics for participation.112 These three 2013 studies found that 1 percent, 2.02 percent, and 3.5 percent of all Tweets gathered during their research collection period included location metadata.113 114 115 Although the data on geolocation participation vary, even at the low end (which would amount to 40 million geolocated Tweets daily), Twitter users share include enough location information in their Tweets to make it worthwhile to study.116 The Twitter Streaming API The aforementioned 2013 studies were possible because, unlike most social network services, Twitter makes a its data publicly available in real-time through an application programming interface (API).117 This enables researchers free access to a large and ever-growing corpus of public and voluntary location data, without the

110

111 112

113

114

Leetaru, Kalev, Wang, Shaowen, Cao, Guofeng, Padmanabhan, Anand, and Shook, Eric.

"Mapping the global Twitter heartbeat: The geography of Twitter" First Monday [Online], Volume 18 Number 5 (22 April 2013)

115

Weideman, C. "Social Media Location Intelligence: The Next Privacy Battle - An ArcGIS add-in and Analysis of Geospatial Data Collected from Twitter.com." International Journal of Geoinformatics 9, no. 2 (2013): 25.

Ibid.

116 117

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Leetaru, Kalev, Wang, Shaowen, Cao, Guofeng, Padmanabhan, Anand, AND Shook, Eric. "Mapping the global Twitter heartbeat: The geography of Twitter" First Monday [Online], Volume 18 Number 5 (22 April 2013) Ibid.

Weideman, C. "Social Media Location Intelligence: The Next Privacy Battle - An ArcGIS add-in and Analysis of Geospatial Data Collected from Twitter.com." International Journal of Geoinformatics 9, no. 2 (2013): 25.

Caverlee, James, Zhiyuan Cheng, Daniel Z. Sui, and Krishna Y. Kamath. "Towards Geo-Social Intelligence: Mining, Analyzing, and Leveraging Geospatial Footprints in Social Media." IEEE Data Engineering Bulletin 36, no. 1 (March 2013).

Leetaru, Kalev, Wang, Shaowen, Cao, Guofeng, Padmanabhan, Anand, and Shook, Eric.

"Mapping the global Twitter heartbeat: The geography of Twitter" First Monday [Online], Volume 18 Number 5 (22 April 2013)

48

need to pay for proprietary data or navigate university research regulations and enroll participants, who may be adverse to personal location tracking studies.118 Twitter’s real-time sample data API, known as the Streaming API, returns a maximum of one percent of all Tweet activity at the time of the query.119 The type of Tweets returned depends upon the parameters set in the query that is sent through the API. For example, one may provide a query to search for Tweets mentioning “cities” would return such Tweets up to the number of Tweets equaling one percent of Twitter volume at that moment. Using less-frequently occurring search parameters returns a greater sample of the overall number of Tweets matching the query. For example, if one were to use the time and location parameters within the query to request Tweets mentioning “fishing” on September 19th in San Francisco, the total number of results would most likely be less than one percent of the current Twitter volume, and one would receive 100 percent of the matching Tweets.120 If the criteria within the query results in a matching number of Tweets exceeding one percent of the current volume of Tweets, the returned data will include rate limit information indicating the number of Tweets that were not included in the results.121 This provides an understanding of the sample size the returned data represents.

Methods for collecting geotagged tweets: An Interview with Eric Fischer An interview with Eric Fischer, a data artist and software developer, provided much insight on geo-located social media data analysis and the process of collecting Twitter data. Fischer, who now works as a software developer and data visualizer for Mapbox in San Francisco, was previously an Artist in Residence for the Exploratorium in San Francisco. Before that, he worked for Google on Android development and at Danger on software development, where he first started writing

118

119

120 121

Caverlee, James, Zhiyuan Cheng, Daniel Z. Sui, and Krishna Y. Kamath. "Towards Geo-Social Intelligence: Mining, Analyzing, and Leveraging Geospatial Footprints in Social Media." IEEE Data Engineering Bulletin 36, no. 1 (March 2013).

Twitter. "How are rate limits determined on the Streaming API?" Twitter Developers. dev.twitter.com/docs/faq#6861 (accessed April 15, 2014).

Twitter. "REST API v1." Twitter Developers. dev.twitter.com/discussions/7140 (accessed April 15, 2014).

Ibid.

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map application software. Fischer’s work has been widely published and has been shown at the Museum of Modern Art. 122 123 124

Figure 21. The Geotaggers' World Atlas #4: San Francisco (Eric Fischer, "The Geotaggers' World Atlas." www.flickr.com/photos/walkingsf/sets/72157623971287575/ (accessed April 15, 2014).)

122

123

124

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Jaffe, Eric. "Mapmaker, Artist, or Programmer?" Atlantic Cities. August 31, 2012. www.theatlanticcities.com/arts-and-lifestyle/2012/08/mapmaker-artist-or-programmer/3132/ (accessed April 15, 2014) Kuang, Cliff. "Using Twitter and Flickr Geotags to Map the World." Fast Company. July 12, 2011. www.fastcodesign.com/1664462/infographic-of-the-day-using-twitter-and-flickr-geotags-to-map-the-world (accessed April 15, 2014).

MoMA. "Locals and Tourists, New York and London." 2010. www.moma.org/interactives/exhibitions/2011/talktome/objects/146200/ (accessed April 15, 2014).

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A long-time collector of historical maps, Fischer’s created his first project that analyzed and mapped social media data in April of 2009. This project, called “The Geotaggers’ World Atlas,” mapped location data attached to public Flickr and Picasa photo uploads, which he accessed via the APIs each company provides.125 He initiated this project hoping to better understand where people preferred to walk and bike by looking at travel speeds between photos. He then used the same photo data in conjunction with geotagged Twitter data to create “Locals and Tourists,” a set of maps comparing which areas locals preferred to those visited by tourists.126 He also created a third set of maps, called “See Something or Say Something,” comparing the locations where Tweets were being posted to where pictures were being taken.127

125

126

127

Fischer, Eric. "The Geotaggers' World Atlas." www.flickr.com/photos/walkingsf/sets/72157623971287575/ (accessed April 15, 2014).

Fischer, Eric. "Locals and Tourists." www.flickr.com/photos/walkingsf/sets/72157624209158632/ (accessed April 15, 2014).

Ibid.

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Figure 22. Locals and Tourists #3 : San Francisco. “Blue pictures are by locals. Red pictures are by tourists.

Yellow pictures might be by either.� (Eric Fischer, "Locals and Tourists." www.flickr.com/photos/walkingsf/sets/72157624209158632/ (accessed April 15, 2014).)

Because he was accustomed to using the Flickr and Picasa APIs, which were search APIs, he started his exploration of Twitter data using the Twitter Search API, but it would only return a handful of results, and so he switched to the Streaming API. Fischer collects a constant flow of geotagged Twitter data using a bounding box parameter that covers the entire world in his query.128 In his experience, he has found that roughly two percent of all Tweets are geotagged, which is a number in 128

52

Fischer, Eric, interview by Meghan Hade. (February 28, 2014).

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line with what has been cited in other research.129 130 131 Using this query system, Fischer receives about 40 percent of all geotagged Tweets as a result of the one percent stream data limit.

Fischer explained the data he collected for one sample day, February 16th, 2013.

On this day, his query returned 4,319,993 geotagged Tweets, and the metadata told him that 7,074,212 geotagged Tweets were not included due to the stream limit. 132 Because the stream has a one percent data limit, he is able to know that a return of 4,319,993 Tweets means there was a total of 431,999,300 Tweets on that day. Using the metadata regarding “dropped” Tweets, he can see that he received 38 percent of all geotagged Tweets, and that geotagged Tweets comprised 2.6 percent of all Tweets for that day.

Fischer has found a number of factors that can influence the location data, and should be considered when analyzing Twitter geodata. First, a number of mobile applications that post geotagged data to Twitter, including Foursquare and Instagram, snap the user’s location to certain coordinates within the area from which they are “checking in.”133 This can lead to a disproportionately high number of tweets occurring at a single Cartesian location, when in actuality the origin locations of these tweets are distributed throughout a wider geographic boundary.

This displacement can be anywhere from a few feet to hundreds of feet, depending on the geographical size of the location. In a small space like Union Square, this would not affect the accuracy of a usage study, but in a larger park, such as Golden Gate Park, this may pose a problem. Additionally, mobile devices will first attempt to gain a precise location via GPS, but will fall back to Wi-Fi signals and cell towers if they are not able to access GPS.134 When this occurs, a tweet’s recorded location is not necessarily as specific as the coordinates of a GPS location. Finally, 129

Caverlee, James, Zhiyuan Cheng, Daniel Z. Sui, and Krishna Y. Kamath. "Towards Geo-Social Intelligence: Mining, Analyzing, and Leveraging Geospatial Footprints in Social Media." (2013).

130 Leetaru, Kalev, Wang, Shaowen, Cao, Guofeng, Padmanabhan, Anand, AND Shook, Eric.

"Mapping the global Twitter heartbeat: The geography of Twitter" First Monday [Online], Volume 18 Number 5 (22 April 2013) 131 Social Media Location Intelligence, 25, International Journal of Geoinformatics , Vol 9, No 2, (2013) 132 133 134

Fischer, Eric, interview by Meghan Hade. (February 28, 2014).

Ibid.

Ibid.

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there are some Twitter accounts that will throw off the data, because they will have a geotag for a certain location, but are not actually tweeting from that location (for example, an earthquake Twitter bot, or automated account, posting a Tweet geotagged with an earthquake’s location without actually being physically present at that location).135 Using geotagged tweets to understand park usage This publicly available geotagged Twitter data could be used to better understand how areas of urban centers are used, where the density of Tweet activity is high. In San Francisco, this data could be analyzed to provide a new source of understanding of park usage by providing park planners quantitative information.

Although the geotagged Twitter data is a sample of the total amount of Tweets created each day, and only a portion of the population shares information via Twitter, it does provide an idea of the trends and variations in park usage throughout the day and year. This type of data could be used to aid in decision making, such as determining whether or not a potential shadow would adversely impact the use of a certain park.

Test Case: Union Square When the San Francisco Recreation and Parks Commission approved the potential shadow on Union Square that would be cast by the 706 Mission development, they did so because RPD planners had determined that they shadow would not adversely impact the use of the park. As RPD Planner Stacy Bradley explained, they made this determination based on an understanding of park usage that was gathered through anecdotal Park Manager knowledge and an observation study conducted by the San Francisco Planning Department in 2012. It was the RPD’s understanding that Union Square was not heavily used in the early morning but that it was heavily used in the afternoon and evenings, and so a shadow occurring during the early morning (before 9:30 AM) in late fall and late winter would not have a negative impact on its use.136 135 136

54

Fischer, Eric, interview by Meghan Hade. (February 28, 2014).

Mauney-Brodek, Karen and Meghan Hade. "706 Mission Street, Evaluation of Shadow Impact on Union Square." Staff report, Capital and Planning Division, San Francisco Recreation and Parks Department, San Francisco, 2013.

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To analyze whether geotagged Twitter data would reflect this understanding and confirm trends in usage of Union Square, a dataset of tweets that included location metadata within a bounding box around Union Square was collected. The dataset included 108,485 tweets that were created between May 14th, 2011 and February 29th, 2014. Of these, 29,094 included only a general bounding-box location and no coordinates. These tweets were filtered out, and the remaining 79,392 tweets were then plotted on a map. Using the RPD GIS shapefile for the Union Square park boundary line, a final dataset was created using only tweets that originated from within the true boundary of the park. This dataset, which eliminated many falsely geocoded tweets (as mentioned by Eric Fischer), contained 17,433 tweets. Figure 23 highlights the areas where the most tweets in the dataset occurred. The orange areas represent the fairly even distribution of tweet locations throughout the park, and the yellow areas represent where the density of tweets was highest.

Figure 23. Demonstrating the density of geotagged tweet locations in Union Square (source: author, rendered through CartoDB. Basemap source: Google)

Using D3, a data visualization library for the JavaScript computer programming language, the data was graphed using a scatterplot format (see Appendix 3 for the D3 script.) This method was chosen because it is an efficient way to create a flexible visualization of a large dataset. This visualization script used a scale to distribute the density and color of the chart points based on the ranges in the given

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dataset, which was important as it allowed opacity to be used, creating darker areas on the chart where there was a higher frequency of data.

Figure 23 shows the Union Square Twitter data plotted on a 24-hour time scale (the y-axis) and over the course of the 34-month period (the x-axis). A low opacity is used on the points so that a density of points appears darker. The darker areas dataset, which was important as it allowed opacity to be used, creating darker reveal trends where usage is heaviest throughout the year. areas on the chart where there was a higher frequency of data.

Figure 23 shows the Union Square Twitter data plotted on a 24-hour time scale (the y-axis) and over the course of the 34-month period (the x-axis). A low opacity is used on the points so that a density of points appears darker. The darker areas reveal trends where usage is heaviest throughout the year.

Time of day

Figure 24. Data visualization expanded to reveal trends over entire period of data.

DateThe

most obvious trend is a consistent lack of Twitter activity during the early

morning hours throughout the entire data time period. Higher levels of Tweet activity, as revealed by darker areas on the chart, occur in the evenings during the

Figure 24. Data visualization expanded to reveal trends over entire period of data.

winter holiday season each year, which is when the park features a skating rink and lit tree, as well as during early fall and late spring afternoons.

The most trendthe is adata consistent lack itofwithin Twitter the uses early a low Figure 25 obvious compresses to visualize a activity narrow during width and morning hours throughout the entire data time period.

Higheron levels of Tweet opacity for each dot, revealing the average trends of activity a 24-hour

activity, as revealed by darker areas on the chart, occur in the evenings during the timescale. Figure 26 breaks down the tweets by the hour they occurred. These winter season each extent year, which is when park a skating rink and shows,holiday to an even greater than Figure 24,the that thefeatures park is on average most

lit tree, as well as during early fall and late spring afternoons. heavily Tweeted-from during the mid-day and evening, with very little Twitter activity during25 thecompresses early morning.

Figure the data to visualize it within a narrow width and uses a low opacity for each dot, revealing the average trends of activity on a 24-hour timescale. Figure 26 breaks down the tweets by the hour they occurred. These shows, to an even greater extent than Figure 24, that the park is on average most heavily Tweeted-from during the mid-day and evening, with very little Twitter activity during the early morning.

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Figure 25 Data compressed to reveal trends on a 24-hour time scale. (Source: author.)

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Figure 26 Tweets grouped by the hour of day they occurred.

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Figure 25 Data compressed to reveal trends on a 24-hour time scale. (Source: author.)

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Figure 26 Tweets grouped by the hour of day they occurred. (Source: author.)

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Usage trends for Union Square: How Twitter data compares to RPD findings To understand how Union Square is used, the Recreation and Parks Department considered anecdotal evidence from departmental Park Mangers and an observation study of the park conducted by the Planning Department in 2012. The Park Mangers, who spend time at the park each day, have gained personal experience over time that allows them to speak about trends in park usage. The Park Managers believed the park was most heavily used in the afternoon and that it is mainly used as a mid-block crossing during the morning. The observation study conducted by the Planning Department recorded the current weather and use of the park on half-hour intervals between 7:00 AM and 9:30 AM on August 28th, 2012.

The study found that the areas people chose to sit in the square during this time was distributed between both sunny and shaded areas, thus showing that shade did not impact the early-morning use. It also showed that the number of people in the park significantly increased within the last hour of the studied time period. The study did not, however, include observations from the rest of the day for comparison, or from another day beyond August 24th, which does not allow for an understanding of the typical trends in park usage.

Analysis of geotagged Twitter data from Union Square for the past thirty-four months echoes the evidence provided by the RPD Park Mangers. Trends in the Twitter data activity suggests that more people do indeed visit the park in the midday and evenings than in the morning hours.

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CHAPTER SIX A Modern Technique for a Classic Inquiry 59

In the previous chapter, we discussed a method for gathering and understanding Twitter data that could help meet San Francisco park planners’ need for park usage data, as required by the city’s shadow policy. We then analyzed a dataset of tweets that originated from Union Square and compared the results to data produced previously through more traditional methods. In this final chapter, we will discuss how to best employ this new method, and we will learn about a project that is currently using it to help parks departments gain an understanding of what is happening in their parks.

Employing social media data analysis as one inquiry within a broader investigation Although the Union Square Twitter data does provide support for the anecdotal evidence frequently used by the Recreation and Parks Department in their shadow review process, it is not a complete solution for understanding park usage.

Geotagged Twitter data is only a sample of the larger Twitter dataset, which itself only provides insight on a sample of the total population. This limitation does not preclude use of Twitter data in analysis, though, as other types of park usage studies face similar challenges, including limitations in population or time. For example, it is not possible to conduct a usage observation study (such as the 2012 Union Square usage study conducted by the San Francisco Planning Department) all day, every day, and so whatever time period is feasibly observed serves as a representative sample for average park activity.

There are additional sources for geotagged social media data that could be collected in addition to Twitter data, such as Foursquare, Instagram and Flickr.137 All of these services provide API access to their content. Studying data from multiple sources would help provide an understanding on a wider demographic of users.

However, because simply analyzing the time and location of data does not provide an understanding of the type of activity the user is engaging in at that moment, this type of study would best serve as one facet of a multi-pronged park usage investigation. The content of data gathered from these various sources could also be studied with regard to sentiment (the emotional tone of the data, i.e. whether the

137

60

Caverlee, James, Zhiyuan Cheng, Daniel Z. Sui, and Krishna Y. Kamath. "Towards Geo-Social Intelligence: Mining, Analyzing, and Leveraging Geospatial Footprints in Social Media." IEEE Data Engineering Bulletin 36, no. 1 (March 2013).

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data conveys a positive or negative message), travel patterns, or topical patterns (such as Twitter hashtags), as demonstrated in Stamen’s parks.stamen.com project.

A practical example of using social media data analysis for parks Gathering social media data for the purpose of park planning and management is a new technique, but it is not untested. Stamen Design, a design and technology studio in San Francisco, recently partnered with the Electric Roadrunner Lab and the Golden Gate National Parks Conservancy, to create a system of parsing social media data originating from California parks.138 This partnership was initiated by Jon Christensen of the Electronic Roadrunner Lab, the Institute of the Environment and Sustainability, the California Center for Sustainable Communities, and the University of California, Los Angeles’ Department of History and Center for Digital Humanities.139 Jon’s research interests lie in the history of California, how the settlement and development of the state relates to the environment, and how social media use relates to open spaces.140 Stamen used park boundary data from the California Protected Areas Portal (www.calands.org) to analyze and visualize the social media data generated within California Parks.141 Alan McConchie, a Design Technologist at Stamen, worked on this project and explained the process they used to develop parks.stamen.com.142 In making this website, they set out to create a tool that would motivate people to visit and support parks and open spaces, as well as a tool for parks administrators.143

138

Stamen Design. About this Site. parks.stamen.com/about (accessed April 28, 2014).

139

Christensen, Jon. "Social Media & Parks." The Field: The Professional Landscape Architects' Network.

American Society of Landscape Architects. March 7, 2014. thefield.asla.org/2014/03/07/social-media-andparks/ (accessed April 28, 2014).

McConchie, Alan, interview by Meghan Hade. (April 17, 2014).

140

141

Stamen. California Open Spaces. parks.stamen.com (accessed April 15, 2014).

142

McConchie, Alan, interview by Meghan Hade. (April 17, 2014).

143

Ibid.

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The site gathers social media data originating in California parks and displays it on a single page for each park. It is also possible to see what parks are most photographed, have the most check-ins, etc. Christensen describes the benefit of using social media data in the following way: “The parks.stamen.com application enables policymakers, managers, and advocates to see what people are doing and saying in the normal course of their interactions with parks and open spaces managed by dozens of agencies, from national parks to state parks, regional parks to neighborhood parks. And it allows park visitors to express themselves and be heard— without having to go to an official hearing.� 144 McConchie explained that parks administrators are usually strapped for resources and often do not have tools for understanding who is using their parks and how the parks are being used, other than in-person observation.145 He noted that using social media data as one indicator of how parks are being used allows the administrators to expand this understanding beyond the park staff hours.146 McConchie also acknowledged the digital divide that exists with regard to who is using social media, and how the socio-economic makeup of social media users does not mirror that of the general public. Despite this, he said, it is still a potential data source that often reflects a greater socio-economic diversity than community meetings often do.

Social media data can also provide insight on issues that may be hard to observe; Alan cited one example where a park trail was eroding at a much faster rate than the park planners believed it would. By looking at what people were saying about the park online, administrators were able to learn that the trail had become a popular trail for CrossFit exercise, and training sessions were being organized through social media. The parks administrators were able to reach out to people

144 Christensen, Jon. "Social Media & Parks." The Field: The Professional Landscape Architects' Network.

American Society of Landscape Architects. March 7, 2014. thefield.asla.org/2014/03/07/social-media-andparks/ (accessed April 28, 2014).

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145

McConchie, Alan, interview by Meghan Hade. (April 17, 2014).

146

Ibid.

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using the trail in this way and recommend other trails that would be suitable for CrossFit training, thus reducing the impact on a single trail.

The project is still in an exploratory phase and Stamen has not yet started to analyze the data they are collecting, but there is already a wealth of information amassed at parks.stamen.com. The searchable site provides access to data for every park in the state. Each park’s page displays recent FourSquare check-ins to the park, photos of the park posted to Instagram and Flickr, and recent tweets that used the park’s unique hashtag (e.g. #UNSQ for Union Square Park). Parks departments, who may not have in-house knowledge about how to collecting this type of data, are able to go to parks.stamen.com and instantly have a snapshot view of what people are sharing on social media that relates to their parks. Union Square’s page (parks.stamen.com/park/12478) lists Union Square’s location (37° 47' 16.55" N, 122° 24' 27" W), links to directions to the park, and names the parks system it belongs to (City and County of San Francisco). According to the page, there are 153 Foursquare venues, or check-in options, at Union Square, and there have been over one million check-ins to these venues. It says that Instagram features 279 photos of Union Square by 254 people, and that 979 people have sent 1,468 tweets mentioning the #UNSQ hashtag.147

147

Stamen Design. #UNSQ (Union Square). http://parks.stamen.com/park/12478 (accessed May 3, 2014).

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Social media data provides a way to understand use of public space At the beginning of this research report, a review of literature on the design of urban public space showed the importance of understanding how a space is (or will be) used. Understanding the actual uses, rather than simply the predicted or desired uses, can help create a space that more closely meets the needs of the entire spectrum of the population.

In The Social Life of Small Urban Spaces, William Whyte’s observational studies of public spaces in New York City used film to visually record how people used the space, and then researchers watched the film and recorded the data for what people were doing—where they were walking, talking, sitting, and standing.148 149 They were seeking to understand the general usage patterns of the spaces they studied, much as this research project seeks to understand the general usage patterns of Union Square. Whyte’s film method was an innovative use of a readily available technology; using social media data to understand usage patterns in small urban spaces is a modern take on his now-widely accepted approach.

148

Whyte, William H. The Social Life of Small Urban Spaces. New York: The Project for Public Spaces. 1980.

Oppenheimer, Mark. "Technology Is Not Driving Us Apart After All." The New York Times. January 14, 2014. http://www.nytimes.com/2014/01/19/magazine/technology-is-not-driving-us-apart-after-all.html (accessed April 27, 2014).

149

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Brenner, Joanna and Aaron Smith. “72% of Online Adults are Social Networking Site Users.” Pew Internet. Pew Research Center. August 5, 2013. www.pewinternet.org/2013/08/05/72-of-online-adults-are-social-networking-site-users/ (accessed April 15, 2014).

The Brookings Institution Center for Technology Innovation. “The “Town Square” in the Social Media Era: A Conversation with Twitter CEO Dick Costolo.” June 26, 2013. www.brookings.edu/ events/2013/06/26-town-square-social-media-twitter-costolo (accessed April 15, 2014).

Caverlee, James, Zhiyuan Cheng, Daniel Z. Sui, and Krishna Y. Kamath. “Towards Geo-Social Intelligence: Mining, Analyzing, and Leveraging Geospatial Footprints in Social Media.” IEEE Data Engineering Bulletin 36, no. 1 (March 2013).

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Appendix 1: San Francisco Planning Code Section 295 Section 295: a. No building permit authorizing the construction of any structure that will cast any shade or shadow upon any property under the jurisdiction of, or designated for acquisition by, the Recreation and Park Commission may be issued except upon prior action of the City Planning Commission pursuant to the provision of this section; provided, however, that the provisions of the Section shall not apply to building permits authorizing: 1. Under 40’ 2. First, last hour 3. RPD buildings 4. Same height, same location as 1984 5. Projects w/ permits already filed b. “The City Planning Commission shall conduct a hearing and shall disapprove the issuance of any building permit governed by the provisions of this Section if it finds that the proposed project will have any a dver se im pa ct on t he u se of the property under the jurisdiction of, or designated for acquisition by, the Recreation and Park Commission because of the shading or shadowing that it will cause, unless it is determined that the impact would be insignificant. The City Planning Commission shall not make the determination required by the provisions of this Subsection until the general manager of the Recreation and Park Department in consultation with the Recreation and Park Commission has had an opportunity to review and comment to the City Planning Commission upon the proposed project.” c. “The City Planning Commission and the Recreation and Park Commission, after a joint meeting, shall adopt criteria for the implementation of the provisions of this Section.”

Figure 27: San Francisco Planning Code Section 295. (Source: The City and County of San Francisco. San Francisco Planning Code. http://www.amlegal.com/nxt/gateway.dll/California/planning/article25heightandbulkdistricts?f=templates$fn=de fault.htm$3.0$vid=amlegal:sanfrancisco_ca$anc=JD_295 (accessed April 15, 2014).)

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Appendix 2: Planning Observation Study of Union Square150

Union Square 08/24/2012 07:00 AM Fog

Exercise Play Sedentary Photos

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San Francisco Planning Department. "Transit Center District Plan Presentation Slides." August 2012.

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Union Square 08/24/2012 07:30 AM Fog

Exercise Play Sedentary Photos

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Union Square 08/24/2012 08:00 AM Fog

Exercise Play Sedentary Photos

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Union Square 08/24/2012 08:30 AM

Exercise Play Sedentary Photos

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Union Square 08/24/2012 09:00 AM

Exercise Play Sedentary Photos

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Union Square 08/24/2012 09:30 AM

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Appendix 3: Munging Process for Twitter Data 1. Tweet data is just text, so open in a text editor and save as a .csv. Then, in excel, import the csv data, and be sure to use tab, comma and space as delimiters.

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2. Only the first 5 columns are important. The 6th and 7th column for some tweets include additional geo-data. We want to delete these tweets, as they don’t have a precise geo-location, only a bounding box location. To delete these, sort by the 6th column, and delete all data for all tweets that have a number in this column. This will help filter out some of the noise. (29094 tweets out of 108485 tweets deleted, 79392 tweets remain)

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3. We only need the Date, time, lat, and lon. Delete all other columns

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4. Timestamp is UTC, so adjust to Union Square location, minding daylight savings time. a. Sort by date and time b. Create new column that combines date and time into one column (so that timeshift moves to previous date if necessary)

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c. Add column for -8, or -7 during daylight savings time periods, which are: i. 2011: March 13 – November 6 ii. 2012: March 11 – November 4 iii. 2013: March 10 – November 3 iv. 2014: March 9 – November 2 d. Add column that subtracts the 7/8 column from the DateAndTime column.

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5. Create new columns to separate date and time (name these date and time, change original date and time name). a. Copy and paste Shifted_DateAndTime into two separate columns, format one as date, one as time b. Copy these two new columns, paste as values only

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c. Delete everything except these two new date and time columns and the lat and lon columns.

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Appendix 4: D3 Script for Generating Union Square Twitter Data Scatterplot <!DOCTYPE html> <head> <meta charset="utf-8"> <script src="http://d3js.org/d3.v3.js"></script> <style> body { font: 10px sans-serif; } .axis path, .axis line { fill: none; stroke: #000; shape-rendering: crispEdges; } .dot { fill: #000; fill-opacity: .15; } </style> </head> <body> <script> var margin = {top: 20, right: 20, bottom: 30, left: 40}, width = 1200 - margin.left - margin.right, height = 300 - margin.top - margin.bottom; var x = d3.time.scale() .range([0, width]); var y = d3.time.scale() .range([height, 0]); var color = d3.scale.category10(); var xAxis = d3.svg.axis() .scale(x)

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.orient("bottom"); var yAxis = d3.svg.axis() .scale(y) .orient("left") .tickFormat(d3.time.format.utc('%H:%M')); var svg = d3.select("body").append("svg") .attr("width", width + margin.left + margin.right) .attr("height", height + margin.top + margin.bottom) .append("g") .attr("transform", "translate(" + margin.left + "," + margin.top + ")"); function time(date) { return new Date( date.getMilliseconds() + date.getSeconds() * 1000 + date.getMinutes() * 1000 * 60 + date.getHours() * 1000 * 60 * 60); } x.domain([new Date(2011, 4, 1), new Date(2014, 4, 1)]); // 2011 - 2014 y.domain([new Date(1000 * 60 * 60 * 24), new Date(0)]); // 00:00 - 24:00 svg.append("g") .attr("class", "x axis") .attr("transform", "translate(0," + height + ")") .call(xAxis) .append("text") .attr("class", "label") .attr("x", width) .attr("y", -6) .style("text-anchor", "end") .text("Date"); svg.append("g") .attr("class", "y axis") .call(yAxis) .append("text") .attr("class", "label") .attr("transform", "rotate(-90)") .attr("y", 6)

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.attr("dy", ".71em") .style("text-anchor", "end") .text("Time of Day"); d3.csv("Data_public.csv", function(error, data) { var dateFormatter = d3.time.format("%m/%-d/%Y"); var timeFormatter = d3.time.format("%H:%M:%S"); data.forEach(function(d) { var date = dateFormatter.parse(d.Date); var time = timeFormatter.parse(d.Time); d.date = new Date(date.getFullYear(), date.getMonth(), date.getDate(), time.getHours(), time.getMinutes(), time.getSeconds()); }); svg.selectAll(".dot") .data(data) .enter().append("circle") .attr("class", "dot") .attr("r", 4) .attr("cx", function(d) { return x(d.date); }) .attr("cy", function(d) { return y(time(d.date)); }); }); </script> </body>

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