Mapping Boston’s Trees Summerville
Caroline Dickensheets Assignment 12.5: Density and 3D Maps URBS 330 For this assignment, I used a dataset provided through Boston Open Data that digitizes trees located throughout the city. The data comes from a planimetric project completed in 2011 and includes trees both within city public ways and properties. The dataset categorizes trees as either being a public street tree (148,528) or a tree in a park (53,317) with the total number of trees reaching over 200,000. Understanding that this number if constantly evolving, I think it is still an interesting way to look at certain areas in Boston and could be matched with certain census data to tell an even greater story. Point Data This first map uses point data to identify every tree in the City of Boston. Displaying point data does a good job at identifying individual units and gives a decent overall picture of where there are higher concentrations of trees. I found that displaying the data this way picked up on smaller trends such as tree lined streets and trees that line rivers. You can even pick up on some form of a city grid in South Boston (south of Logan Airport) just by following the line of dots created by the identified trees. Areas of high tree concentrations that I could identify included along the Charles River, and areas along water in general, except for
Charlestown
Cambridge
Charles River Reservation Allston
Boston Public Downtown Garden & Commons Back Bay
Logan Airport
South End
JFK Presidential Library
Brookline Jamaica Pond
Forest Hills Cemetery
the immediate downtown area. Back Bay with its tree lined Commonwealth Ave. and the Boston Public Gardens and Commons also show a significant amount of points, all to be expected. The area of Allston seems to have higher concentrations in general. Finally, the Forest Hill Cemetery also appeared to be an area with an abundance of trees. This area also includes the Franklin Zoo, an Audubon Nature Preserve, and other green spaces that would increase the number of trees.
Summerville Charlestown
Cambridge
Charles River Reservation Allston
Boston Public Downtown Garden & Commons Back Bay
Density Mapping Because the points are displaying a higher resolution of data, you get a better idea of where specific places within the city have higher numbers of trees. However, it does not do a good job at demonstrating the overlap of trees in larger areas. For this purpose, density maps can provide insight into larger trends. In this case, what areas of Boston have higher concentrations of trees overall? While individual point data might be useful for identifying where more trees could be added, density maps such as these could be coupled with health data or general information from the census to see if there are any correlations with the number of trees in the area. This density map uses an output cell size of 500 ft. and a search radius of 2640 ft. Immediately, there are some areas identified with having a high number of trees that the point data map did not. These areas include the South End and Fenway neighborhoods. East Boston Memorial Park also shows up in this map with more force than in the point data map.
East Boston Memorial Logan Airport
South End Fenway JFK Presidential Library
Brookline Jamaica Pond
Forest Hills Cemetery
Median Income One of the first complexities with mapping data in Boston is comparing city collected data to census data. Suffolk County, which contains Boston, expands outside the city limits. Therefore, while I have data for most of the tree locations in the City of Boston, I do not have this same data for a few of the census tracts that are outside of city limits. These appear to be north of Boston. This map overlays data on a census tract’s median income level (either above or below the median). I thought it would be interesting to see how the density of trees impacts an area’s affluency. I would assume that higher income areas would have a greater number of trees while those that are less affluent would have a smaller number. I assume this because trees often indicate amenities such as parks and are seen as assets for a city. Overall, this map does support the idea of trees leading to higher median incomes in an area. This is especially true in the Back Bay and South End neighborhoods. On the other hand, areas with lower income such as Dudley Square, Roxbury, and Dorchester tend to have a lower density of trees.
Summerville
Cambridge Logan Airport Allston Back Bay South End
Brookline Dudley Square Roxbury Dorchester
Allston
3D Mapping 3D maps adds another dimension to this map that can be both insightful‌and confusing. Due to the complex geographies of Boston, I found it difficult to orient myself in the space. Besides this, the 3D map does highlight some of the differences between tree densities that the regular density map does not. For example, you get a better idea of how many more trees there are in Allston. The area around the JFK Presidential Library also shows a high peak of trees that I did not anticipate. Overall, I think using the 3D map is interesting for this case, because trees do grow upward. Unlike census data that is one dimensional, it makes sense to represent something that exists in our physical world using three dimensions.
Brookline
Fenway JFK Presidential Library
To summarize, I think that the density map does an effective job at illustrating overall city trends in comparison to the individual point data.
JFK Presidential Library Allston
Sources: County Shapefile: 2010 TIGER/LineÂŽ Shapefiles: Census Tracts Cambridge Boundary: City of Cambridge, MA Summerville Boundary: City of Sommerville, MA Brookline Boundary: City of Brookline, MA Census Data: Social Explorer, American Community Survey (5-Year Estimates), 2012-2016 Tree Shapefile: BostonGIS, accessed through Boston Open Data Hydrography: BostonGIS, accessed through Boston Open Data Boston Boundary: BostonGIS, accessed through Boston Open Data
Cambridge
Brookline Brook Farm