Google has announced sweeping changes to its map services, including improved 3D views for Google Earth, an offline mode for Google Maps as well as a Street View Trekker initiative. Google Earth received textured 3D buildings in 2006 and it will soon display 3D models in entire metropolitan areas on mobile devices.

The company says this is possible because of its new imagery rendering techniques that allow it to generate 3D cityscapes with buildings, terrain and even landscaping from 45-degree aerial imagery. It plans to have 3D coverage for metro areas with populations of at least three million people by the end of the year.

New 3D imagery for Google Earth for mobile

Although Google's digital map service is an incredible resource, there is one inherent shortcoming: it requires an Internet connection. Users have long requested an offline mode and the company will finally address that demand. In near future, Android users will be able to take maps offline from more than 100 countries.

When prodded at its San Francisco event, Google remained tight-lipped about the offline feature, saying that it would share more details in the coming weeks. However, the company said it was safe to assume that if Google Maps Navigation is supported, offline and 3D would be too (suggesting 2.x devices may be supported).

Purported image of Apple's iOS 6 Maps app

Google Trekker backpack camera

The company wants to add these features to all platforms eventually, but rumors are circulating that Apple plans to introduce its own map service for iOS devices next week (June 11 to 15) at the Worldwide Developer Conference, which would presumably end the iPhone-maker's longstanding partnership with Google.

Speaking with unnamed sources in May, 9to5Mac reported that the iOS 6 Maps application will provide a cleaner, faster and more reliable experience for iPod, iPhone and iPad owners. BGR has since posted leaked photos and, for whatever it's worth, Apple purchased 3D mapping company C3 Technologies last October.

Google's Street View cars, trikes, snowmobiles and trolleys have reportedly driven five million unique miles and collected 20 petabytes of imagery data. Although Street View vehicles will continue collecting data the company says "wheels only get you so far."

To get off-road, the company has developed a backpack camera dubbed Trekker. "There's a whole wilderness out there that is only accessible by foot. Trekker solves that problem by enabling us to photograph beautiful places such as the Grand Canyon so anyone can explore them," the company said.