Question about SRTM

Good evening. I was going through the process to determine ground deformation of a small area using sentinel 1 images. I was wondering why srtm is selected as default option for the DEM by the software. I understand other DEM can be used, but why srtm and not for example ASTER is automatically downloaded? A particular reason? Particular characteristics of this dem? Special algorithms in the software?
And for the deformation, as external DEM is it better a global DEM or a national elevation model?


One of the main reasons is probably that SRTM is open to use and can be integrated in the software for automated download. Furthermore, you don’t have to explicitly agree to terms and conditions (like with ASTER).

Which DEM is generally better for your study strongly depends on the location and nature of your study area. There are plenty of comparisons which demonstrate the pros and cons for various data sets: