Global Mapper is more than just a viewer capable of displaying the most popular raster, elevation and vector datasets. It converts, edits, prints, tracks GPS and allows you to utilize GIS functionality on your datasets in one low-cost and easy-to-use software package.
Global Mapper also includes the ability to directly access multiple online sources of imagery, topographic maps, and gridded terrain data. Global Mapper includes access to worldwide high resolution color imagery from Digital Globe/GlobeXplorer/AirPhotoUSA (watermarked access for free) and access to the entire TerraServer-USA database of USGS satellite imagery and topographic maps free-of-charge. Global Mapper also has the ability to easily access WMS data sources, including built-in access to elevation data and color imagery for the entire world, and to view elevation data in true 3D with any loaded raster imagery and vector data draped on top of it!