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
Last revision 20/7/2021