[GIS] the difference between DEM data sources

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I have started experimenting creating basic 3D elevation models in QGIS recently. It turned out for me that there are several free sources of DEMs, like USGS's EarthExplorer, CGIAR-CSI's Digital Elevation Database and also EU-DEM from the Copernicus Program.

As far as I could have found out, the best resolutions of these data are the following:

  1. SRTM elevation data from USGS's EarthExplorer site is available in 30 meter resolution – 1 arc second
  2. SRTM elevation data from CGIAR-CSI site is available in 90 meter resolution – 3 arc second
  3. SRTM elevation data from EU-DEM site is available in 25 meter resolution – 1 arc second

Is there any significant difference between these data sources and their accuracy?
Especially between USGS EarthExplorer and EU-DEM? I would like to use data of Europe and european cities so when I say difference, I mean the resolution, accuracy or quality and not the geographic coverage.

(Basically, I would like to find out which source is the best choice for a 3D model and I cannot see the difference between the American and the European DEM)

Best Answer

With regards to your question of the difference betwen SRTM and EU-DEM the ESA quotes:

The EU-DEM is a hybrid product based on SRTM and ASTER GDEM data fused by a weighted averaging approach and it has been generated as a contiguous dataset divided into 1 degree by 1 degree tiles, corresponding to the SRTM naming convention.

As they mention ASTER I and the term "hybrid" I would skip this data set. ASTER had major issues as it is an optical system. I would work with SRTM-1 data as it has exetnesive coverage in terms of quality analysis and the physics and methods behind the data are "defined".

I've written some comparisons for a non-urban area: ASTER vs. SRTM 3 and ALOS vs. SRTM1 I hope this helps somehow!

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