Global DEMs from OpenTopography

Guth and Kane (Transactions in GIS, 2021) suggest that Copernicus is the best choice among these.  ALOS World 3D would be the second choice.

DEM and its properties OpenTopography Metdata and location to start download
Pick link for the data set you want
Precision File numbers and size for complete data set Notes
Copernicus DEM OT.032021.4326.1 Float 26,440 files, 550 GB Resampled to same arc second spacing in x and y if you select by box, which changes the data characteristics.  Some countries missing for political reasons.  Goes farther north than SRTM and NASADEM.
ALOS World 3D AW3D30 v 3.2: OT.112016.4326.2 Integer 23,997 files, 220 GB Not void filled.  They have the averaged data from the 5 m source; JAXA also has median
NASDADEM OT.032021.4326.2 Integer 14,251 files, 128 GB HGT files, stored as TIFF here
SRTM v3: OT.042013.4326.1 Integer 14,280 files, 125 GB Unclear which 3" version they have (middle or average)
USGS 1" 3DEP/NED merged with DEMs from Canada and Mexico OT.012021.4269.2     Terrible choice for name, since it is not just USGS but international.  Perhaps not surprisingly, this has disappeared without explanation that I can find.
Global Multi-Resolution Topography and bathymetry OTGMRT.112016.4326.1      
SRTM 15+ (land/ocean merge; the 15 arc second resolution is about 450 m) OTSRTM.122019.4326.1      

You must have GDAL installed, via OSGEO4W, to use the DEMs in MICRODEM.

The grids use -9999 for missing data without indicating this in the Geotiff header.  You should mark it missing on Import/Export, or editing the grid, if the color scheme is distorted by the invalid large negative elevations. 

DEM results will be in tar.gz (Unix) compressed file.  Compress/Decompress option in MICRODEM will use decompress with 7-Zip without bothering you with the details.  If you do multiple downloads you must segregate them in different directories, as they decompress with the same names and some of the decompressions will fail.

General instructions for Open Topography

Key Global Regional DEMs

Last revision 20/7/2021