Does somebody know where you can find the relative orbit number of a Sentinel 1 image? I know it should be somewhere in the metadata (the xml-file), but I can't find it.
[GIS] Sentinel 1 relative orbit
sentinel-1
Related Solutions
For the quick and dirty way to find out if it is ascending or descending, it is easier to look at the start (or end) time. For instance, in Belgium, you get the ascending images at around 5 PM and the descending ones at around 6 AM. So, in the string YYYYMMDDTHHMMSS, if the first H is 1, I know for sure that the image has been taken on an ascending orbit. The time is in GMT, so you need to adjust it based on the timelines if you are not at the same longitude.
If you want to make sure, you can use gdalinfo to open the safe file
gdalinfo yourS1folder.SAFE/manifest.safe
and look at the ORBIT_DIRECTION in the metadata
EDIT: if you know roughly where you are, some regions have specific acquisition plans with ascending only, descinding only or both, as you can see from the image below from ESA sentinel website, valid since february 2018.
Best Answer
You actually can find the relative orbit number of sentinel-1 image from the filename by deriving absolute orbit number provided in the name.
The formula are:
Sentinel-1A Relative Orbit Number = mod (Absolute Orbit Number orbit - 73, 175) + 1
Sentinel-1B Relative Orbit Number = mod (Absolute Orbit Number orbit - 27, 175) + 1