Tuesday, 10 September 2013

The Age of Buildings in the City of Chicago

Following my last post, on the geography of New York City, I've been exploring other building-level datasets to see what they can offer us in relation to telling us more about the fabric of the cities we live in. This time, I've focused on Chicago's 'Building Footprints' dataset. It's not nearly as detailed as New York's PLUTO data but it does include variables on (e.g.) number of floors and year built. As with the NYC data, it is not perfect but we can still make good use of it to understand the development of the city and its structure. I've mapped the city using number of floors as a proxy for height and shaded it by building age to produce the following overview (blues = older buildings, reds = newer).

Besides looking relatively interesting, the above graphic also reveals something about the phased construction of the City of Chicago and - possibly - something more about the data itself. As with the New York City PLUTO data, I produced a chart of the 'year built' column just to give me some idea of its distribution. It looks better than the New York City chart but I'm still not convinced it is 100% accurate (the year built data run from 1852 to 2010). 

Were there really nearly 15,000 buildings constructed in 2006 and only 78 in 2000? Possibly, but it would be good to know more about the accuracy of the data. In total there are 820,154 building footprints in the dataset and there are a range of different columns - which you can read more about in the metadata file. Once again, it's pretty cumbersome to work with in a normal desktop GIS setting but my machine can just about handle it.