As I am working behing a strict company proxy, from time to time I face large problems to make SNAP work. For this reason, I have implemented a manual download of S1 orbits, in which the proxy settings are properly considered. In the same line, I would like to download the DEMs manually for processes such as
Terrain-Correction. My question is, where can I get these files?. At least the tipical DEMs used for Sentinel-1 - SRTM 3 sec, 1 sec, etc.
There are other use cases that would benefit from a simple process to download data files: people working on ships or remote field sites but also need to do some work with SNAP, and air-gapped systems. Maybe an “offline” mode could replace the download attempt with a recorder to generate a list of URL’s to be downloaded along with their target locations. There may be a way outside SNAP to record the URL’s, but currently SNAP experiences timeout timeout delays and processing failures.
Most URLs for the DEMs can be found in the
snap.auxdata.properties file. It is in the
etc folder of the SNAP installation directory
I may be mistaken, but I assume that many auxiliary file downloads are for specific times or areas, so only a few files from a DEM repository with global coverage are actually downloaded. These DEM URL’s are helpful, but a user would need to figure out which files cover their region-of-interest.
dem_autoload looks very useful, but not easily discoverable. It might be good to have a document for “offline use cases” to collect offline upgrading and offline DEM downloads and extra detail (not everyone is familiar with