Earth to iPhone

"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," notes Peter Birch, Google Earth product manager, on the Official Google Blog.

"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 3-D terrain. You can even browse any of our 8 million Panoramio photos or read Wikipedia articles," he adds.

The application, which also works with the iPod touch, is available free from Apple's (Nasdaq: AAPL) App Store, either via iTunes or directly via an iPhone.

With or Without GPS

Google Earth for iPhone can use the built-in GPS sensor in the iPhone 3G or use Apple's cell tower and WiFi location services to get a read on the iPhone's position. Those familiar with Google Earth will appreciate the "fly to" animation that brings users to a zoomed-in location.

Tilting the iPhone can adjust the view of mountainous terrain, and using multi-fingered swipes can zoom, tilt or spin the view. The app also comes with two layers -- one for geo-located Wikipedia articles, which launch Safari upon use, and another for Panoramio geo-located photos. Panoramio lets users click on small square icons that launch user-posted photos from around the world.

Both layers can be turned off.

No More Rumors

A similar application, Earthscape, was released by Churchill Navigation earlier this year, sparking rumors of an official Google Earth app.

"I was anticipating it. I think it's great. I was very impressed that is does such a great job of giving the same look and feel as the full application, even though it is limited in its abilities [compared to the full Google Earth desktop application]," Frank Taylor, publisher of the independent Google Earth Blog, told MacNewsWorld.

Offline Earth

One handy feature of Google Earth for iPhone comes via cache storage that keeps copies of the maps stored in the iPhone for offline use.

"I turned on Airplane Mode on my iPhone, tried it, and sure enough it pops up with a requester that asks if you want to go off network," Taylor explained.

"If you had already visited places, if you zoom in, you can still see those places even if you're not online. And that's the way Google Earth has worked as well -- a lot of people don't know that -- you can use Google Earth without an Internet connection as long as the places you're visiting are in your cache," he added.

Taylor isn't sure what the size of the cache memory is, but the maximum cache setting in Google Earth desktop is 2 GB, he said.

"The main thing is, being a computer graphics person -- I've worked in 3-D for a long time -- I'm very impressed with the speed of it considering the limited power of an iPhone," Taylor said. "Even on the AT&T (NYSE: T) Edge network, I was impressed. It was loading the imagery, just slower [than via WiFi]."

Google's Phone

The iPhone, it turns out, is still getting lots of traction at Google.

"We've seen significantly greater usage of mobile applications on the iPhone than on other mobile platforms," Aaron Stein, a spokesperson for Google, told MacNewsWorld.

Still, what about the Google-backed Android mobile device operating system?

"We expect Google Earth to be available on future Android handsets, but we don't have a date to confirm at this time," Stein said.

Google Earth for iPhone is available immediately in 18 languages and 22 countries.