NASA World Wind is available as a full install, or as an update to a previous release. You may use it under the terms of the NASA Open Source Agreement.
System Requirements
Windows 95, 98, ME, 2000, or XP
Intel Pentium 3, 1 GHz, or AMD Athlon or higher
256 MB of RAM
3D Graphics Card
nVidia GeForce 2 Ultra
ATI Radeon 7500
Intel Extreme Graphics 2
DSL / Cable connection or faster
2 GB of disk space
Notes
World Wind benefits most from a video card with 3D acceleration. If you don't know whether your machine comes with one, it is likely to have one built in if the computer was purchased within the past two years. Here is a list of video cards that have been reported to work with World Wind.
World Wind requires that you have .NET runtime environment and DirectX installed. You can download .NET runtime environment and DirectX runtime.
World Wind comes with data you can zoom into. After a certain point, World Wind will begin to download more images automatically. The servers hosting this information are very busy and may be unresponsive until we get the necessary infrastructure.
这个居然免费，而且公开源代码~~！
下面是用那个的截图
