These are the worst of the worst. 500 out of 10,000 is only 5 percent. The clearing of land into large parcels will need to be a long iterative process. This cut addresses the ones that are way too far gone. Conversely, the map does not show a relationship to current neighborhood density. Therefore one house on a block might be all that is needed to clear the whole block. You would need to zoom in closely, flip the map to areial, and know if anything has been built or removed since the date of the last flight. In addition, these internet map companies are not very savy with areials and sometimes fly with full leaf cover. This diminishes a lot of what you can get out of an areial.