I pulled shapefiles of building footprints for nine major cities in the US, calculated the areas of the building footprints (outlines of buildings at ground level) and mapped them. All mapping and calculations were done in a sinusoidal projection with a local meridian. The color scheme is consistent from map to map, but the scales are not (white bar = 5 miles).

These maps allow you to differentiate between city centers, industrial areas, and residential neighborhoods. You can also see variations among housing size in some areas, though the scale prevents you from delineating individual buildings. (Some of the shapefiles contained >1M buildings, which ArcGIS couldn’t render at 300 dpi.) Anyway, I hope the urban planners out there enjoy this!

Data sources:

https://data.cityofnewyork.us/Housing-Development/Building-Footprints/tb92-6tj8

https://data.cityofchicago.org/Buildings/Building-Footprints-Deprecated-December-2013-/6mpq-sfwi

http://www.portlandoregon.gov/bts/article/268487

http://gis.dallascityhall.com/EnterpriseGIS/shapezip.htm

http://www.pasda.psu.edu/uci/PhiladelphiaAgreement.asp?File=http://www.pasda.psu.edu/philacity/data/PhiladelphiaBuildings200712.zip

http://data.denvergov.org/dataset/city-and-county-of-denver-building-outlines

http://dcatlas.dcgis.dc.gov/metadata/BldgPly_3D.html

https://data.baltimorecity.gov/Geographic/Building-Footprint-Shape/deus-s85f

http://www.mass.gov/anf/research-and-tech/it-serv-and-support/application-serv/office-of-geographic-information-massgis/datalayers/ftpstructures.html