In the latest installment of Kevin Kelly’s Cool Tools, Alexander Rose shows how to use Google Earth to provide cost-effective GPS mapping in real time:
I have been doing a lot of exploring and surveying in the desert recently, and have been trying to find the right GPS mapping solution. The solution I found incorporated stuff I already had (laptop and GPS) with the help of some excellent, nearly free software. The best part is that it works even better than the $900 in-car GPS solutions as it uses always up-to-date satellite data, and is easily sharable.
Basically you run Google Earth and use some great donation-ware to link it in real time to a GPS. This means that your mapping software and maps worldwide are not only free, but you also get hi-res satellite views and in some cases 3D buildings (in downtown areas).
The trick of this hack is getting Google Earth to work offline, when you’re disconnected from the Internet, by updating the cache for your destination before you leave. Alexander’s favorite part if his setup allows him to save a route and share it with others. Check out his post for complete software, hardware, and connection details.