When free is all you can afford, the elevation models below are excellent resources to use in your next GIS, geospatial and/or remote sensing project. For projects requiring higher resolution or more recent coverage than the free DEMs offer, an Apollo Mapping representative would be happy to discuss the various options. You can reach us here at any time.
This is the best known free elevation dataset that exists with coverage between 60° North and 56° South at 30 meters (m) in the USA and 90 m elsewhere. SRTM data has a 16-m vertical accuracy specification (Linear Error 90%, LE90). As it was collected with radar technology, it should be your first DEM choice in cloudy regions.
You can download free SRTM data at these locations:
Created from stereo pairs collected by the medium resolution satellite, ASTER, the GDEM offers 30-meter coverage between 83° North and 83° South. The original version of the GDEM featured at least 20-m (LE90) vertical accuracy which was improved with the release of the second version.
You can download free GDEM data at these locations:
This is the best available public elevation dataset that can be found for the United States. The NED dataset features 10 m resolution over every state except Alaska where it is mainly 60 m. NED is created from a variety of data sources and is updated once every two months. In limited locations, 3-m DEMs are available.
You can download free NED data at these locations: