Last week I had the opportunity to try Tableau, data visualization software used to create a wide range of maps and graphics from large data files. For my testing, I decided to use a Portland Buildings Footprints data set downloaded from the CivicApps website. The file includes every building in Portland with specific geographical location and some other data like building heights, area, volume, roof type, year of construction, etc.
Mapping is a great way to understand geographic patterns that may be missed if you were to use a more traditional chart type, such as a bar graph. An example of that is the “year built” map I was able to create from the data file. The Tableau software geographically locates every building from the latitude & longitude listed in the data file, and assigns a color depending on the year it was built. It also varies the size of the square of the depending on the building volume data.
I originally thought of making a brief animation showing a time lapse of the construction of these buildings. The video is a bit misleading, as it only shows currently existing buildings and not previous/demolished buildings. However, it still gives an idea of how the city in general has expanded throughout the years. The effect is like a heat map to identify areas of the city that are older or newer.
It is also possible to zoom in specific parts of the map to better visualize development in some areas. In order to show this I zoomed in a part of downtown and compared building development from 20 years ago. It was interesting to recognize areas of the city that have gone through a major and noticeable development like The Pearl District in the north, South Waterfront, and OHSU area.
Buildings Height Map
The data file also included average height for each building and I thought of creating another map with this data. Once again each building is a square in the map and it’s average height determines the square size and a color from a gradient. Is interesting to notice the different areas where buildings are higher, it can almost be read as a zoning map.