一边读某贴俺一边放狗,先这里存一下。。
1. Quantum GIS Downloads
Quantum GIS (QGIS) is a user friendly Open Source Geographic Information
System (GIS) that runs on Linux, Unix, Mac OSX, and Windows http://download.qgis.org/downloads.rhtml
2. USGS Free Topo map download http://store.usgs.gov/
then click on "Map Locator" in the middle of the page.
3. Free Digital Elevation Model (DEM) and Free Satellite Imagery Download Links http://www.terrainmap.com/rm39.html