25 million sounds impressive and it indeed is. Most of those footprints are for large U.S. cities and metros. Los Angeles, Chicago, Miami, Houston and the San Francisco Bay Area are some of the areas where the changes will be most obvious. The additions however will also touch on the whole United States.
But how did Google manage to add so many new footprints? It is, of course, using aerial images and combines this raw data with computer vision processing to come up with dimensions and shapes for buildings.
“This process enables us to provide more building footprints and a more comprehensive and detailed map than ever before,” Google said.
Actually, this is the same core process used in Google 3D Maps. In the meantime, if you're still wondering whether Google Maps is being developed for iOS and the iPhone 5 the answer is not clear. It's all under consideration, and lastly Google CEO Larry Page said that while he would like Google to serve Maps to all platforms, the walled-garden approach (like the one in the App Store) stops or at least slows that down.
source: Google Latlong