Does the Google Earth App for iPad Need an Internet Connection?by Edward Mercer
Unlike Google Earth on the computer, which is entirely Web-based, Google Earth for the iPad is an application you download and save to the device. The Google Earth app draws information and maps from the Internet as an alternative to saving data for the entire globe on your hard drive and is designed to work with a Web connection. However, you can run the program in a limited way when you're offline using the cache on your iPad to save map data for offline use.
iPad Cache Considerations
Google Earth functions on an offline iPad only because the device stores recently viewed map tiles in its cache for faster viewing. While the computer version of Google Earth allows you to change cache settings to increase memory, no such option exists on the iPad, and offline functionality is limited but possible.
Preparing to Go Offline
Clear the cache of any old information in the Google Earth app by clicking the wrench icon to open the Options window and tapping "Clear Cache." Approve the selection in the confirmation dialog box to get started with all the space possible in your cache. Then display the tiles you want to be able to see offline on your screen by entering a location in the search box. The Google Earth app saves the tile data to your iPad cache. The cache space is limited; depending on the amount of data and layers on the tiles, you may only be able to save a few frames. New cache files save over older ones, so verify your cache content by going offline and seeing which tiles are available.
When you run the Google Earth app without an Internet connection, the areas saved to your cache appear exactly as you saw them while running Google Earth for the last time with a Web connection. You can use the Google Earth app functionality to move around the map. The application itself is functioning off your iPad using the images stored in its cache, but the rest of the globe is not be accessible until you reconnect to the Internet.
The Advantages of Being Online
In addition to being able to see maps for the entire globe while online, using Google Earth with an Internet connection on your iPad also allows you to access high-data features like 3-D images of cities and buildings.