Nov 16, 2015

Visualizing urban growth

The things that happen in Seattle; amazing.
From Seattle's Open Data website:
"Here's a fabulous example of what can be done with data from data.seattle.gov. Using Processing, (www.processing.org), Zubin Rao created an animation depicting Seattle building permit activity, charting permits by location and animating the permits based on dollar amount and issue date. The size of the circle is based on the dollar amount of the construction cost and grows to full size over the course of a year. As the time slider on the right descends, circles from previous years "ghost" out and disappear."
Mapping the quantity and intensity using building permit data allows construction value to serve as a proxy indicator for where urban growth is occurring. The analysis could be tuned further be filtering the results to show specific types of occupancy: Residential, Industrial, etc and new floor area vs alterations. This can be used to show spatially, which areas are adding new commercial square footage; what neighborhoods are undergoing conversions of uses: industrial to commercial, and so on.

One of the challenges of doing this in Honolulu (and perhaps elsewhere) is that properties are tracked by tax map keys. Legal and real property tax boundaries change over time: consolidation, resubdivision, dropped parcels, etc. When this occurs, it is difficult to track the continuity of permit activity through time. Sometimes permits get "lost," which leads to undervaluation of permit activity. DPP does seem to tag properties by census block group number (which also changes over time, although perhaps not as much as TMKs); not sure if permits are also assigned to CBG.

Another great app on the site: Seattle in Progress, shows the spatial location of Land Use Permits mapped around the city. Users can access further details about each project. I can learn more about proposed and accepted permits in Seattle, than i can in Honolulu.

Here's one example: https://www.seattleinprogress.com/project/3016806 by Perkins and Will. At the end of the presentation is the visual rationale for the "random" block forms -- they evolved from curves in a much older, traditional structure into the seemingly randomized block form, below.