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March 31, 2009
Using Google Earth Offline
One of Google Earth's speed features also has the benefit of enabling the application's use when Internet is not available. The key is the Google Earth cache file which stores imagery and other data locally on your hard drive. This speeds up your experience even when you have broadband Internet, but it also is the secret to offline GE use.
By using the GE cache, you can still use most of Google Earth's features while on an African Safari, while driving your car, while boating offshore, or just camping on a mountain. This includes the aerial/satellite imagery, the 3D terrain, and more. And, the iPhone Google Earth app has this feature as well. If you anticipate taking your computer (or iPhone) somewhere where you won't have an Internet connection, you can still use GE. Or you can use it for doing a demonstration somewhere without an Internet connection. You will need to do a little preparation first.
First, go to the menu item Tools->Options and select the "Cache" tab. You will not need to change the memory cache for viewing the cache (there is a trick for storing the cache with this setting - see below). The memory cache is set automatically based on your system's memory. You can make the disk cache size as large as 2000 MB (i.e. 2 Gigabytes). This will give you more data to work with. Then, you need to move to the area you want data for and zoom into that area. The most recent things you have looked at will be what's in your cache. It's important you zoom to the closest view you think you'll use. Turn on other layers for information you want cached (for example, 'Terrain', 'Roads' and 'Borders' - the more you select, the faster the cache wil fill). Also, make sure you save any KML files you might want to use in files on the same computer.
The more data you cache, the sooner the cache will fill, so be cautious. If you're going on a long trip, cache in high resolution imagery just the areas where you plan to use GE for close viewing. Avoid turning other layers if you only need imagery. It can be a pain to move around and capture an area of imagery at full high resolution and load up your cache properly. FreeGeographyTools has written some nice tutorials for some free tools for loading your GE cache in a more automated fashion - see here, here, here, and here. There is also a way you can save the cache files to extend the amount of area you can store (see this forum thread),
The GE offline capability can be really useful. I've used it personally for driving in a car, traveling by plane, and while sailing. There are still places without broadband or even cell phone connectivity. But, Google Earth can still work even in those remote places. Amazing!
Posted by FrankTaylor at March 31, 2009 8:20 AM
Comments
Posted by: Andy at April 1, 2009 4:28 AM
I like to "burn" detail into my cache for airplane flights: I make a temporary set of placemarks and then run a looping tour between them to get the detail where I will need it. I often travel with my GPS so I can be quite accurate about where I am even if clouds obscure the view.
A couple of years ago I'd done this for a flight between Toronto and Vancouver. I'd been working on a quote and the woman next to me kept "peeking" at the spreadsheet. When I closed Excel, GE was already running under it, and I repositioned the view to match where we were. This really caught her attention, and she made no attempt to be surreptitious.
She was fascinated, and it turned out she was going home to North Vancouver. As it happened, I'd used a placemark for a relative there so when I moved GE to North Van, the detail was excellent. Even better, she lived quite nearby, so I was able to zoom in to where she could see her own house -- and their camper trailer parked in the drive! She was so excited she could scarcely write Google Earth in her notebook so she could get her husband to download it.
And I still think she somehow missed my explanation that the view was not live...
Posted by: Eric at April 3, 2009 11:30 AM
This is indeed a very good facility of Google Earth can also be used offline. I am sure it would help the users a lot.
Posted by: GPS at April 22, 2009 5:18 PM
This is great!
I've got a question about saving KMLs. When I try to save a "My Maps" map, the KML simply contains a link to an additional file stored on the internet, so I still can't access the placemarks on my map without being online. Is there any solution to this?
Posted by: Eve at June 2, 2009 8:00 PM
@ Eve: (*Link to web site with malware removed*). The simple answer to your question is to save the KML to your local drive. You can then view the KML with Google Earth - which does work offline. You may want to cache the imagery and other layers you want to view while off line as well.
Posted by: Frank Taylor 
at June 2, 2009 9:17 PM
Sorry about the malware. I've been trying to figure out what the problem is and it's a mystery!
Posted by: Eve at June 6, 2009 12:15 PM
How do I set the directory Google Earth uses for cache? I have a PC that is used by mutiple people and the current default stashes cache under the user files which makes things slower and bloats the PC. (This should have been a setting via options all along IMO.)
Posted by: BobH at September 3, 2009 3:56 PM
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You can also use the Flight Simulator F16 and SR22 cockpits overlays offline if you download copies of the images to your local drive and change the KML files to point to these files instead. Just delete the http call to the URL and replace with the path to the file eg c:\Users\User\Pictures\filename.png
This allows you to fly with the cockpit overlays over areas of cached scenery offline, when the website hosting the overlays is offline or the overlays are no longer available, or when you want to use your own custom overlays.