Google is looking to expand the reach of Google Earth with a new browser plug-in and API released Wednesday that allows developers to infuse 3-D geographic views into Web applications.

The new tools will let users "fly" over different venues on Earth or access other features of Google's digital globe without having to run the client installation of Google Earth. Google hopes the plug-in and API will make Google Earth as popular among developers as the company's Google Maps application, whose API now runs on more than 150,000 sites, noted Paul Rademacher, technical lead for the Google Earth plug-in and API.

"We recognize that there are tens of thousands Map API sites," he said. "We want those to all be 3-D enabled very easily, so we're making it possible for existing sites to be 3-D enabled with a single line of JavaScript code. What's been missing [in Google Earth] is the ability for developers to use Google Earth inside their own Web pages. Now inside a Web page you'll be able to fly through San Francisco or see a 3-D model of a cabin with exactly the view out the window of the mountains."

Rademacher said he expects Google Earth to be particularly popular on real estate sites so people can get a 3-D view of houses and on travel sites where consumers can see the view from a hotel room.

Google said key features of the API include:

• 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 placemarks;

• The ability to view the thousands of existing 3-D buildings, or add a developer's own 3D models; and

• Support for switching to Google Sky mode for high-resolution imagery of stars, planets, and galaxies.

Google made the Google Earth announcement in conjunction with its Google I/O developer conference that got underway Wednesday in San Francisco.

"This is a relatively rare example of Google releasing a new technology to developers first," Rademacher noted. "Now we're very comfortable with the fact that developers do great things when you give them a new tool."