Yisha Su
Introduction
Building footprints represent the full perimeter outline of each building as viewed from directly above. As an urban planner, I have been dealing with building footprints and shapefiles to create maps in Geographic Information System(GIS). This time I was curious about what insights I can get from analyzing the data of Building Footprints in Tableau Public.
Materials
I used NYC Open Data to search and export the dataset into a CVS file of Building Footprints. Then I added the dataset to Tableau Public, a free, cloud-based application for filtering, analyzing, and visualizing data, to analyze and create the visualizations.
Process
In the beginning, I downloaded the CVS file of Building Footprints data. After I downloaded the data, I put into tableau and checked the Attribute Information, which includes: “Building Identification Number (BIN); Borough, Block, and Lot information(BBL); ground elevation at building base; roof height above ground elevation; construction year, and feature type” [1].
Sheet 1. Building Height in NYC
The first digit of BIN is a borough code (1 = Manhattan, 2 = The Bronx, 3 = Brooklyn, 4 = Queens, 5 = Staten Island), so I group those values into five variables. Then I put the Borough into columns and Heightoof (the height of the roof above the ground elevation) into rows and changed the measure of Heightroof to Average. As I expected, the average building height of Manhattan is the highest. Besides, I marked each borough into different colors by dragging Brough into Color.
Sheet 2. Total Construction Area by Borough
Then I started to analyze the amount of building built by years. I put Cnstrct Yr (the year construction of the building was completed) into columns and Shape Area into rows. I marked each borough into different colors and filter years from 2000 to 2020. I also filer the second sheets with boroughs, so when combined the two worksheets into the dashboard and click a specific bough in the Building Height diagram, the Total Construction Area will the changes of the certain borough.
Sheet 3. Total Construction Area
I used the same data in Sheet 2, but this time I did not mark each borough into different colors. Instead, I marked Shape Area with black to red gradient colors. The more the total area is, the more reddish the color.
Results
Reflection
The average height of Manhattan is the highest. Yet during the past 20 years, the total building area in Manhattan is the lowest because the buildings in Manhattan are already saturated. The overall trends of construction amount went up in 2000 to 2005 and reached the crest at 2005, followed by decreasing trends in the flowing years and reached a low point in 2014, the year financial crisis happen. Then the same curve repeated, which increasing till 2017 and then went down to the lowest point in 2020 when the pandemic outbreak (also the 2020 data are not completed as well).
If I were to continue further with this project, I might add borough boundaries and visualize them on a map, which can help people who do not have the knowledge better understand what boroughs are.
Reference
https://github.com/CityOfNewYork/nyc-planimetrics/blob/master/Images/FeatureViews/Build_Foot.png
