For a site in Manhattan, just by using Google Earth and drawing a 1/4 mile circle is easy to see that the density is met without any issues.  But for sites near open spaces, or in suburban areas, what is the best way to document this credit?  Use Google Earth and the ruler to measure out the roads and then estimate the footprints of buildings?  Use an Autocad file, if available from the Design Team, to measure footprints and do calculations of areas?  Go to the tax assessor website and try to find the buildings within the radius?  All of these seem to take a large amount of time.  Is there one way that reviewers prefer to see?