Google Earth is looking to expand, with a new browser plug-in and application programming interface (API) released today that allow developers to infuse 3-D geographic views into Web applications.

With the help of new tools, users can access Google’s earth  without the client installation of Google Earth. This is likely to make all thousands of Maps API sites get 3-D enabled.

Key features of the API include the following:

• The ability to embed Google Earth inside any Web page with only a few lines of code
• A JavaScript API to enable rich Earth-based Web applications
• Support for manipulating KML and the 3-D environment to create polygons, lines and place marks
• The ability to view the thousands of existing 3-D buildings or add a developer’s own 3-D models
• Support for switching to Google Sky mode for high-resolution imagery of stars, planets and galaxies