Also here, what do you expect by using a DEM of this high resolution for coregistration? The DEM is only used to estimate the offset between both images based on terrain features which are also present in the raw radar data (no radiometric calibration applied).
I don’t think you need a DEM with 1m at this step already. Later, for Topographic Phase Removal or Terrain Correction it makes more sense.
I used ACE30 for the BackGeocoding and later the 2m DEM (I reported in the other topic) and this worked fine.
DEM-based coregistration tries to find patterns which exist both in the DEM and the backscatter intensity. If the images are not of equal size or resolution these patterns cannot be found and no GCP are created and the coregistration fails.
(NB: I didn’t use the Graph Builder, I choose the desktop command for each step).
The problem is at Tophografic Phase Removal step. I will use a 1m DEM that is bigger then the subsett area, EPSG: 4326, nodata value: 0.0 . I’m think that something is wrong with my 1m DEM because if a use Topographic Phase Removal with EXTERNAL DEM Autodonload SNAP works.
I will send you a mail with my DEM, hope you can look up at it and suggest me if there is somethink wrong.
if you use the external DEM no AutoDownload is necessary. This only includes the DEM resources which SNAP can access by itself.
If the BackGeocoding works with ACE30 or any other DEM (SRTM, in case your study area is covered) you can still use the external DEM in the topographic phase removal. Do you get an error here?
yes, the problem is that when i use AutoDownload DEM SNAP works, but when i try to use my DEM that has a higher resolution (1m) than the AutoDownload one, SNAP doesn’t works. There is not a specific error but i have no output.
yes. In fact after BackGeocoding if I use AutoDownload dem for Topographic Phase Removal SNAP works…
That’s the reason why I suppose that the error is in the DEM that I provide (when I play Topographic Phase Removal with external DEM).