A three-dimensional view of the Matterhorn in Switzerland. The blue boxes can be touched to display photos of the mountain. (Google)

Google Inc. has taken its popular three-dimensional map software Google Earth mobile by releasing it for Apple Inc.'s iPhone and iPod Touch.

"Even before we introduced Google Earth back in 2005, the team had long dreamed of being able to carry the Earth around in your pocket," wrote Peter Birch, a Google product manager, on one of the company's blogs on Monday. "It may be small, but it brings all the power of Google Earth to the palm of your hand, including all of the same global imagery and 3D terrain."

The software is available for free for the iPhone and iPod Touch in 22 countries, including Canada, through Apple's app store.

Like the desktop computer version, the mobile Google Earth uses satellite photos to render a three-dimensional globe that users can "fly" around. Users can type in a location, fly to it, then look at it from the air, and zoom in or out using the iPhone and iPod's touch screen.

Many locations also have photos and Wikipedia articles associated with them, which users can look at by touching the icons on screen.

The mobile version of the software also makes use of the motion sensor on the iPhone and iPod Touch, which allows users to view three-dimensional terrain — such as mountains — by tilting their device.

The iPhone version of Google Earth also makes use of the device's GPS function, which allows users to search for locations or businesses near them. Google is looking at extending its search-advertising into the mobile software.

"Geographic mapping as a business for Google is a great opportunity. We wouldn't be in it if we didn't see it as a major bottom-line contributor," Birch told CNET. "We're absolutely looking at and experimenting with ads in Earth as well."

Although known as a data-intensive application, Google Earth is well compressed in its mobile version. In a 10-minute test session, the mobile Google Earth used slightly more than five megabytes of data over Rogers Communications Inc.'s 3G wireless network.

As with many 3G applications, however, the mobile Google Earth drains the iPhone's battery quickly.

The mobile version of the software lacks some of the desktop functions, such as three-dimensional building models, but Google is working on adding them soon, Birch said.