The DC Office of Zoning (DCOZ) is using the Google Maps API to provide a comprehensive zoning map for the District of Columbia. The DC Zoning Map allows users to determine the zoning classification for any property in the District.
When you zoom in on a property on the map you can learn different things from the map. You can find out what zoning district the property is in. Zoom in further and you can find the block number (the official ID the city has for a particular block). Zoom in even further and you can find the lot number for a building and see the building boundary.
Also SeeAddison Zoning Map - zoning and ordinances map for Addison, Texas