USAPhotoMaps 可以联机至 http://terraserver.microsoft.com/ 下载 USGS (United States Geodedic Survey) 卫星照片，而你只要调整 GPS 卫星定位的经纬度，再按一下"Download Map Data"，就可以将空照图下载回来，并可以拉近 / 拉远。

Version 2.76
Sept 3
Adds capability to move the screen up and down with the mousewheel,
and left and right with the mousewheel and the Ctrl key held down.
Select Scroll on the Menu to see this info.