DEM generated from SLC image pair 2021


I am trying to generate DEM from a pair of of SLC in Makkah City (arid region, less vegetation). The temporal baseline 12 day and perpendicular baseline 153 m. I following @ABraun tutorial as well. I attached ss image of my processing and the coherence and phase unwrapping looks quite good even the elevation is much different compare to SRTM. When try to processing DEM in GIS, there are river/stream network which not connected, different with SRTM. its mean my DEM results still not good?
I need your input and correction. Thanks for your response



I think the results are pretty fine for repeat paas InSAR. Yet, hydrological runoff modelling requires quite accurate DEMs. The Sentinel-1 DEM could still contain local artefacts which lead to unexpected flow direction and accumulation.
May I ask why would you prefer the Sentinel-1 DEM over DEMs by SRTM or Copernicus?

Thanks @ABraun. I am using sentinel dem in order to study the impact of the anthropogenic effect on the hydrological response. There are rapid and big construction project which change the landcover/clearing area in my study area. I also used another DEM like HydroSHED, ASTER, ALOS, and MERIT to make comparison. Based on the result, Sentinel-1 has significant different compare to the others DEM like stream network, geomorph hydrograph, etc.
Now I have doubt, should I create a new DEM again or not? btw why there is no 6 day temporal baseline in my area? it different with your turtorial in Turkey.
also, how to download DEM from Copernicus? i have try to download it before but it said access denied.

a 12-day pair will probably always contain some distortions. You can try another pair, but the quality will always be minor compared to SRTM or Copernicus. Have you multi-looked your interferogram to a coarser resolution (as most are 30m)? This could prevent some smaller errors?

The Copernicus DEM can be downloaded here after registration here.

Based on ASF baseline tool, 6 day is not avaiable in my study area.

Yes i have ‘multilooking’ the interferogram after Goldstein Phase filtering. in Phase to Elevation, i used SRTM 1sec HGT (auto download).

Regarding DEM Copernicus, i have this message when i try to download the DEM. Access forbidden. I heard it can access only from Europe member, is it correct?

I thought the Copernicus DEM was available for anyone. You can use other 30m DEMs, such as SRTM or ALOS W3D30.

I try again to download Copernicus DEM but the results same like this