1"/3" SRTM Files
Shuttle Radar Topography Mission data was first released in early 2002, two years after the ten day mission flew on the space shuttle. By early 2004, 3" data for North America, South America, Eurasia, Africa, Australia, and islands was available. Only the polar regions are missing. 1" data for the US was also universally available initially, and has now being released worldwide after initially being available only for the US military. This is still the best DEM at the global scale. The mission did not cover the poles, leaving 20% of the landmass vacant.
SRTM is probably of better quality than the ASTER GDEM, but lower quality than the 1" USGS NED/GDEP. The biggest problem with SRTM is holes, which occur mostly in two settings: very steep mountains, like the Himalyas, when steep canyons and ridge sides often were not seen by the sensors; and dry sand in the regions like parts of the Sahara where there were no reflections
3" SRTM (DTED 1)
|North America||2417||2.46 GB|
|South American||1814||2.10 GB|
|Total||14585||15.4 GB||35 GB|
SRTM hole filling projects. Noble goal, but remember that you cannot easily turn lead into gold. But for visualization or hydrology, removing the holes is important.
Using SRTM data:
MICRODEM does not perform a vertical datum shift for this data, which you must consider when comparing SRTM data to other DEMs.
Relation of SRTM3 (DTED 1) to SRTM1 (DTED 2):
Last revision 1/3/2017