What is the difference between SRTM and NED?
A. The table below shows the differences. Basically, the advantage of using the SRTM over the NED is that SRTM is more current. This would especially be important over mining and quarry areas. The elevation from the NED is bare ground readings whereas SRTM is reflected surface based. To read more about the SRTM go to http://srtm.usgs.