The Space Syntax for Railway Recycle Intervention Process and Urban Regeneration Sub-Theme 5: Smart/Intelligence
First Author Georgia Institute of Technology, College of Design, Huang, Jiaxuan, North Avenue, Atlanta, GA 30332 e-mail: jhuang389@gatech.edu
Second Author Southeast University, School of Architecture, Dong, Jia, #2 Sipailou Road, Nanjing, China, 210096 e-mail: 230159622@seu.edu.cn
Abstract This paper discusses the use of Space Syntax for performance assessment in railway recycle intervention. It is intended to explore the actual effect of urban regeneration triggered by railway recycle and its potential to enlarge the effects of attractive destinations connected by the renewed railway which originally existed in its broader urban context. The space syntax serves as an appropriate methodological tool to measure the performance of an intervened urban system. The case subject of this paper is the evaluation of the built portion (2.5-mile long Eastside trail) of Beltline of Atlanta, an urban design project designed to insert new public transportation system, add green space and attract redevelopment. Though the construction of the whole Beltline calls for decades to be completed, it is generally observed that a transformation process in the environment has already started around the built portion, this paper tends to read its intervening performance under place attractiveness evaluation perspective by Whyte (1980), and Space Syntax method, proposed originally by Hillier and Hanson (1984). From Whyte’s perspective, public space should be assessed by four key factors: access/linkages, uses/activities, comfort/image and sociability, in this method both qualitative and quantitative evaluation is included. The Space Syntax serves as a complementary approach which evaluates the urban regeneration effect in three modelling levels: axial, segments and visibility. The research also includes diachronic perspective of scenarios of each time periods (before, during and after) in order to allow more accuracy in systematic comparison as well as finds out to what extent the intervention has performed merits on the system. This paper is part of wider research that aims to track the ongoing effect of the built portion of Beltline that this experience maybe extended to other portions of Beltline and contribute to the creation of a strategic model of assessing the performance of urban regeneration triggered by railway recycle. Given the fact that many human society has walked pass the industrial age worldwide, if these railway recycle processes demonstrate ability to achieve improvements in their radius of influence, many potential areas will find their intervention solution in similar strategies.
Keywords: Beltline of Atlanta; Railway recycle; Place attractiveness evaluation; Urban Regeneration; Space Syntax
1. Railway Recycle Intervention Process According to urban development pattern, economic developed areas contains massive amount of
industrial wasted land, while developing areas are still constructing and utilizing industrial land. Many former industrial cities still preserves its industrial remains and heritage buildings. Although those left-over land may have lasted more than centuries, and maintain as wasted lands in the contemporary cities, they‟re still imposing long and lasting structural influence to the formation of the new city. In the past, especially in developing countries, when dealing with these old land, the city planning strategies was about reconstruction after a complete demolishment. To industrial contamination areas, the strategies goes further into demolishment, bury and destruction, causing the history, culture and spirits of the waste land to vanish completely. In recent decades, some cases of waste land renewal selectively abandoned simple and rough solutions and attempted to transfer the industrial waste lands to theme parks, dinning and recreation area, art area and residential zone. And land use of these former waste lands has shifted from transport to greenspace, residential, civic…etc. From the perspective of landscape and outdoor space, as urban land value increases rapidly along with the progress of urban development, land is occupied by buildings and transport space, making park and recreation spaces too scarce in the amount to meet the demand of urban residents, meanwhile, urban sprawl has cause the urban environment to jeopardize. Therefore, cases of exploration emerges on the landscape renewal design aiming to reuse the wasted area and infrastructure, famous ones among them includes Sudgelande Natural Park, Germany, Striped Railway Park, Kyoto, Japan, Highline Park, New York city.
2. Methodology To figure out the urban renewal effect by Eastside Trail, Beltline, a diachronic methodological approach was established. Timeline 2002.4 was selected to represents the old railway situation before the construction of Eastside Trail, Beltline began-the phase “yesterday”. In parallel, the recent situation of Eastside Trail, Beltline in use, was considered “today”. Comparison was made between the two time nodes to reveal the change in the quality of public space and its morphological characteristics. The latter one is measured by space syntax method as a complimentary tool. To evaluate Eastside trail, Beltline in the perspective of public spaces quality, the study applied place attractiveness theory developed by Whyte (1980) and evaluation framework from Public Space Organization (1975). In the framework, the quality of public space is assessed by four key parameters: access/linkages, uses/activities, comfort/image and sociability, in this method both qualitative and quantitative evaluation is included. On site survey was used to evaluate the above parameters, including direct, indirect observations and place experience.
3. The Atlanta Beltline: Methodological Approach 3.1 Yesterday, intervention and today – urban context and morphological characterization
Figure 1.Left: Main part of Eastside Trail, Beltline. Right: Historical evolution of Eastside Trail, Beltline Source:left: Heinberg, Richard. "Creating a Public Realm for the Twenty-First Century." What Makes a Great City. Island Press/Center for Resource Economics, 2016. 275. Right: drawn by the author.
Prior to 2000, various urban issues existed in the urban development of Atlanta, including urban sprawl and the extent of urban development which may have been gone ahead of its time. The residential and commercial parts has encountered a series of negative effects of the unplanned urban development, including long commute distance, air quality deterioration, dependence on vehicles and limited public spaces. The urban sprawl situation went further to aggregate the uneven economic development situationwhile its metropolitan area are developing at a unprecedented speed, work opportunity increases tremendously, recession and urban blight were existing within the city of Atlanta. Though it is estimated that by 2030, the number of residents in city of Atlanta will increase by 150,000, and the population of the Atlanta metropolitan area will rise from 3,700,000 to 6,000,000. Inner city neighborhoods, especially those in the west and south will suffer from continuous recession. In 1999, the concept design of the Atlanta Beltline was proposed by Ryan Gravel in his masterâ€&#x;s thesis, a city planning student at Georgia Institute of Technology. Originated as a transit urban renewal proposition, the thesis suggests the imaginary scenario of transferring the old railroads into transit corridors. The Beltline redevelopment plan was approved by the Atlanta city council in 2005 including its tax increment financing scheme. In the same year, the Atlanta Beltline Partnership was established to promote the Beltline proposal and Atlanta Beltline, Inc. to implement the project.
In its official statement, The Atlanta Beltline is said to offer “a pedestrian-friendly environment which promotes walking, jogging, biking, and affordable housing……Once it‟s fully built, it will constitute a 22-mile continuous corridors and extensions, providing parks of 1,300 acres, 33 miles of multi-use trails, 22 miles of pedestrian-friendly rail transit, outdoor art exhibition space(“Art on the Atlanta Beltline”), 5,600 units of affordable workforce housing and 1,100 acres of brownfields remediated”(ABI, 2005). The Eastside Trail is the first constructed portion of the entire ring of the Beltline. The portion is 2 miles in length from 10th Street & Monroe Drive to Irwin Street. In the urban context, it connects Piedmont Park, Atlanta Botanical Garden, Historic Fourth Ward Park, the Stone Mountain Trail and Freedom Park. The concept of Atlanta Beltline Eastside includes the existing Eastside Trail as well as its northern and southern extensions. The Entire Atlanta Beltline East starts from Buford Highway to Glenwood Avenue, this is to leave room for future development of the potential to connect to the MARTA King Memorial Station and a tunnel under Hulsey yard (ABI, 2005).
3.2 Place attractiveness parameters to measure the built environment of Eastside Trail The Place attractiveness theory and methodological framework established by Whtye (1980) and the Public Space Organization (1975) evaluates the 4 listed parameters: The Access & Linkages property measures a public space‟s connection with its surroundings. Its intangibles are listed as follows: Continuity, Proximity, Connected, Readable, Walkable, Convenient, Accessible. The comfort & Image property intends to evaluate the expression the public space impacts on its users. Its intangibles are listed as follows: Safe, Clean, Green, Walkable, Sittable, Spiritual, Charming, Attractive, Historic. The uses & Activities property measures the activities on the given public space, which is embodied in place characteristic. Its intangibles are listed as follows: Fun, Active, Vital, Special, Real, Useful, Indigenous, Celebratory, Sustainable. The sociability property measures people‟s interaction in the given place regarding to its place characteristic. Its intangibles are listed as follows: Diverse, Stewardship, Cooperative, Neighborly, Pride, Friendly, Interactive, Welcoming.
Figure 2.Place attractiveness parameters evaluation summary Source: drawn by the author.
3.3 Syntactic models to evaluate the effects of railway recycle process The physical character of grid configuration of Eastside trail, Beltline was evaluated in UCL Depthmap software. The paths (including official paths and shortcuts) was drawn from pedestrianâ€&#x;s perspective. The study boundary is set as a half-a-mile radius (10-minute-walk in urban design influential area perspective) from the 2-mile paved version of Eastside trail, Beltline. A comparison was made between the old railway and after the railway recycle intervention in connectivity and integration parameters. To enable a clear
observation, the color range of both situations are set as the same, with red as the highest level and dark blue the lowest.
Figure 3.Connectivity value before and after railway recycle intervention. Source: drawn by the author.
Figure 4.Integration value before and after railway recycle intervention. Source: drawn by the author.
Figure 5.Histogram of Integration values before and after railway recycle intervention. Source: drawn by the author.
Table 1. Standard Deviation value before and after railway recycle intervention.
Before Intervention After Intervention
Integration [HH]
Integration [HH] [R3]
0.249510924 0.236123356
0.581649478 0.568731745
Source: drawn by the author.
Without checking on the values, it would seem like that more axes would appear more integrated in the “yesterday” condition (2002). Actually, the core of accessibility has been shifted from pedestrian pavements along side the long major roads in the West, East side of the area and along North Avenue NE to the around the central area of North Avenue NE and Glen Iris Dr NE. Pedestrian-only area did not exist prior the Eastside Trail was built, and the shift of core has make it closer for pedestrian-only area to be accessed by two major roads.
Standard deviation of the roads has decreased from 0.250 to 0.236（Integration HH）, and 0.582 to 0.569(Integration HH R3), indicating the construction of Eastside Trail, Beltline has made the accessibility distributed in the whole area more averagely, mostly making the former extremely less integrated roads more accessible in the central area of half-a-mile radius, an evidence of public benefits to its surroundings.
Figure 6.Axial Intelligence before and after railway recycle intervention. Source: drawn by the author.
From the on-site observation, The Eastside Trail‟s design intention has been realized in built form and be received by its users.
Table 2. Axial Intelligibility value before and after railway recycle intervention.
Before Intervention After Intervention
Integration [HH] [R3] 0.38416433 0.413011023
Integration [HH] [R5] 0.198272179 0.215935436
Integration [HH] [R9] 0.146184252 0.148459252
Source: drawn by the author.
Axial intelligibility is defined as the correlation between axial connectivity and axial global integration. “Axial intelligibility indexes the degree to which the number of immediate connections a line has is a reliable guide to the importance of that line in the system as a whole. A strong correlation, or „high intelligibility‟, implies that the whole can be read from the parts.(Hillier B, 1987)” We can see from the table 2 that axial intelligibility value have gone up from 0.384 to 0.413(R3), 0.198 to 0.216(R5),0.146 to 0.148(R9), indicating the construction of Eastside Beltline Trail has converted its half-a-mile radius area into a more legible and readable area than the past, one step closer to become a successful public open spaces.
From the on-site observation, the construction of Eastside Beltline Trail has changed the spatial meaning of the area. However, many factors could explain the change in the nature of the pedestrian flow. Further research needs to be done to clarify the weight of rise in accessibility in all the factors contributes to the improvements in accessibility.
The step depth map evaluates numbers of steps taken from one spot to all other spots in system, in other words, the accessibility from specific destinations planned alongside Eastside Trail, Beltline. Overall, the step depth analysis concludes that connections have been set up from and to Eastside trail, Beltline in many locations, providing it as a reasonable hub to travel between different destinations. The color range is set at the same range of 8 analyzed areas, axes colored dark blue represents the closes distance, while the red color represents the most distant axes.
Figure 7.Step depth value from interest destinations alongside Eastside Trail, Beltline. 1. Ponce City Market ; 2. Shopping & Dinning area; 3.Historic Fourth Ward Park; 4. Art on the Beltline; 5. Historic Fourth Ward Park Splash Pad;6. Freedom Park Trail; 7. The Carter Center; 8. Historic Fourth Ward Skatepark Source: drawn by the author.
Eastside trail, Beltline provides a more accessibility conditions to reach these destinations, and thus enhance the relationship between the destinations. The accumulation of these destinations verse visa makes the Beltline an attractive structure.
The above maps looked into the step depth parameter, which measures the number of steps from one axis to all other axes in a system quantified the potential of visual relationship with the rest of the urban system at each interest destinations locations, in terms of both visual and physical accessibility. The blue color represents the closest level of accessibility, while the red color represents the most distant level. The analysis reveals each interest destination‟s relationship with the Beltline. As for Ponce city market, it has strong walking relationship with the Beltline, as the Eastside Trail serves as its east border. It‟s four edges are all accessible, the North edge on Ponce De Leon Ave NE presents as the main access due to more entrances. As for shopping and dining area, though this area spreads a long span near the Beltline, the access and exit from the Beltline is limited to 2, under a deliberate safety consideration to control the entrances and exits. The analysis predicts most of its visitors coming from the existing roads rather than the Beltline, as the designed consequence of the safety concern. As for Historic Forthward Park, it is mostly accessible from existing roads, such as North Avenue NE, N Angier Ave NE, Morgan St NE, Rankin St NE. As an important node and performance stage provider within the urban design concept, It's not accessible to access or exit from the Beltline, limiting visitors with strong propose. As for Art on the Beltline, the exhibits are distributed everywhere on Eastside Trail, Beltline and its North and South extensions. It‟s the most accessible planned elements of the Beltline to the whole urban system, especially its Westside users. As for Historic Fourth ward Skate Park, Rankin St NE and Ralph McGill Blvd NE, Dallas St NE are the closest three roads to access to, and a relatively closer distance to the Beltline than Historic Fourth Ward Park. As for Freedom Park Trail, It more behaves like a paranell system alongside the Beltline. As their function overlaps, the two trails were designed to make transaction possible, and the analysis also proved the mutual distant accessibility. The Carter Center is the secondly most distant place of interest nearby the Beltline. As a NGO, it has limited connection with the nearby roads, and the Beltline was never designed to be coordinated with it. Historic Fourth Ward Skatepark‟s analysis presents the least accessibility with Eastside Trail, Beltline.
The gap between the analysis and on-site situation lies in the possibility for people to access the Historic Fourth Ward Skatepark from various dispersion that officially but mildly devided the edge.
3.4 Results and discussion
“There is a clear influence of the physical environment in the life style adopted by society and how people interfere with the space, contributing to its transformation” (Hillier e Hanson 1984).
The methodological strategy to identify Beltline Eastside Trail‟s transformation effect on itself and its surrounding urban environment can be concluded as the follows:
3.4.1 Typology of the intervention subject: The railway recycle intervention has changed the basic characteristics of the subject element. Previously, the railway serves as a transport infrastructure, with the basic function of trains circulation. As the back side of buildings near the railway and an urban blight area, it was not considered a pedestrians paths to go. The built and paved Eastside trail portion becomes a public space for recreation and has achieved parameters of place attractiveness evaluation, as to be demonstrated in the syntactic analysis.
3.4.2 Connectivity The Atlanta Beltline Eastside trail has changed the configuration of the urban grid. The old railway behaved as a barrier that separates its west and east side has turned into a permeable area that causes the movement pattern to change fundamentally, as measured by the connectivity values in the axial map analysis. In the scope of the local urban system, the total connectivity values have changed from 2,762 to 3,701. The dramatic rise in the connectivity values suggests that the place has become more accessible, providing more meeting place. It could also be indicated that more social proximity interactions tends to happen in the area.
3.4.3 Integration The Global integration analysis measures all axes in the overall system and indicates the “cores”- axes predicted to be most accessible, permeable and used area in the whole system, also indicating a greater ability to create movement. In the scope of the local urban system, the total integration values have changed from 985 to 1184. Meanwhile, we can see the integration cores in the urban system have changed greatly.. The color range setting is the same for before and after diagram (0.39, 1.70), though the old railway (yesterday) has more integrated axes and at the same time more highly unintegrated axes in numbers than the Beltline Eastside trail(today), the integration core was at long avenues and nonpedestrian roads , although there‟re pedestrian lanes on those roads, the results still indicates from a vehicle perspective. In the Beltline Eastside trail version, higher integration values have been distributed more evenly to the around areas, indicating multi-centers are created alongside the Beltline area, in parallel with the fact that multi-attractions are distributed alongside the Beltline area. The Beltline Eastside Trail didn‟t pop out to be one of the integration cores out of expectation. The whole paved 2 mile only have 5 planned access. It was designed to have limited access points under the belief that this could reduce crime and purify the purpose of people going on the Beltline. As the result of the partial rejecting attitude with the surroundings, the Eastside trail itself are not more casually accessible than the surroundings, but the alongside destinations has been benefited from the emergence of the Beltline.
3.4.4 Place Attractiveness: 3.4.5 Diversity
Various events were planned on the beltline. Direct observation has proved that all the planned events and activities are held regularly as the Atlanta Beltline, Inc. organization has claimed. From the integration analysis above, it‟s dubious that the physical feature of Eastside Trail, Beltline itself absorbs pedestrians randomly, but the deliberated planned activities and nearby land uses contributes to the most of pedestrian flow. It‟s needed for cities and public spaces to have diversity to maintain urban vitality and sustainability (Jacobs 1961), thus diversity should be seen as equally important factor as place attractiveness. To what extent the pedestrian flow of Eastside trail rely on the activities held on the beltline as well as its surrounding land uses remains to be evaluated. It‟s speculated that the physical character reveal by the road network arrangement of Eastside trail would not be as important as the results of policy factor and zonings. The primary model for evaluating Eastside Trail, Beltline‟s impact on the urban context is drawn below as the comparison between “yesterday” and “today”.
Figure 8.Primary model to evaluate effects of Railway recycle intervention Source: drawn by the author.
4. Conclusion:
This paper analyzed the Atlanta Beltline Eastside trailâ€&#x;s impact on its influential area in the urban system of the Atlanta City, Georgia. It is concluded that the railway recycle intervention process has imposes transformations to the railway itself and all nearby urban systems in the following aspects: typology, accessibility system, place attractiveness, and diversity.
The fact that Atlanta Beltline Eastside trail serves as one effective case of railway recycle intervention has proved that this type of intervention could imposes punctual action on its surrounding urban environment as well as positive effects on the urban system. The evaluation strategic model demonstrated in this study could be extended to other railway recycle interventions. Diverse types of railway recycle interventions may have diverse effect on its urban system. Other cases still to be researched to apply the methodology in this case. The features revealed in this paper of Eastside trail, the most mature built portion could be compared with field research on this particular portion and give feedback to design in other potions. Future goal is to compare the Atlanta Beltline Eastside trail to other railway recycle interventions in Atlanta and other cities to make a hierarchy of positive intervention effects on the urban environment. Railway recycle intervention has proved itself an effective urban regeneration method, we‟re looking forward to keeping track of the performance of its future.
Acknowledgements I would like to express my sincere appreciation to my advisors, Professor Richard Dagenhart of the School of Architecture at Georgia Institute of Technology and Professor Wang Yi of college of architecture and urban planning, Tongji University. Your offered irreplaceable advices and support.
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