Google announced that it has expanded its coverage of building footprints in Google Maps, adding 25 million new ones on the desktop and mobile versions.

This includes coverage in Houston, L.A., Chicago, Miamai and the San Francisco Bay Area.

So you have a good idea of how much this has expanded, here’s what a section of Houston looked like in Google Maps before:

Here’s the same section now:

Here’s a neighborhood in San Diego:

“For areas that you’re familiar with, you can also help ensure that the building footprints are accurate and up-to-date by using our community mapping tool, Google Map Maker,” says Google Maps engineering manager Bobby Parikh. “In addition to improving the shapes, you can also assign your favorite local business to an existing building or draw the building footprint for that business using Map Maker.”

“For example, I enjoy exploring and updating the map around Detroit, Michigan, where I lived for many years,” says Parikh. “Now, whenever I go back for a virtual visit, I won’t have to imagine where all the buildings were in my old neighborhood since their footprints have been added for the world to see on Google Maps!”

The building footprints are created algorithmically by Google taking aerial imagery and using computer vision techniques to render the building shapes.

Google has been adding a lot of imagery for its different views in Google Maps lately, but it’s nice to see Google improving the regular Maps view as well. Earlier this week, Google also launched a couple of new Google Maps APIs for location-enabled apps.