Google has just released version 3.1 of Google Earth for iOS, an update that includes native iPhone 4 support and also the ability to explore the world’s oceans.

The first striking change is the quality of the imagery on the app. That’s because Google() has added Retina Display support for the Google Earth() iPhone app, which makes exploring the planet an even more enjoyable experience.

What really makes this app worth downloading, though, is the addition of bathymetry and ocean content. Underwater bathymetry gives you the ability to go under the surface of the ocean and explore the world’s ocean beds. The new “Ocean” layer adds information and content on some of the most interesting landmarks of the Pacific, Atlantic, Indian and Arctic oceans. Much of this information is derived from content curated by the Sylvia Earle Alliance, as well as data from Wikipedia().

Google Earth for iPhone and iPad are now up-to-date with their Android() counterpart, which added the “Ocean” layer last month, yet another update that makes Google Earth one of the coolest tools in Google’s arsenal. You can download the new version of the app here.

Today Google unveiled Earth View in Google Maps, a feature designed to bridge the gap between the popular map application and Google Earth.

The new view — available to those that have installedGoogle Earth — is a remarkable next step for the application and offers 3D perspective with high-resolution imagery, terrain and cityscapes. Essentially Google Maps now supports multi-dimensional world discovery in much the same way that Google Earth does.

“Earth view offers a true three-dimensional perspective, which lets you experience mountains in full detail, 3D buildings, and first-person dives beneath the ocean,” Product Manager Peter Birch wrote in a blog post. “The motion is fluid, and you can see the world from any viewpoint.”

In order to drive home the utility and power of 3D landscapes, Google has created 36 Earth View showcases of world-renowned places and wonders — think the Taj Mahal, Tower of Pisa and the Titanic — which are accessible in the left-hand menu of Google Maps.

After just a few minutes with Earth View, we’re already quite impressed. It’s not often that Google introduces an alternative way to view the world in map form, and this one’s a winner. You can play around with Earth View yourself, or watch a video demonstration of it below.