I am new to radar and I seem to be stuck on a thing. I am trying to download two SLC scenes for the same areas, one from 2015 and 2017 and perform some time series change detection on them. My problem is that I cannot find two coincident scenes, is this normal? I was thinking that maybe I should download some other scenes, that have the same common area I am interested in and subsample, but I am not quite sure how this might affect the processing afterwards. Can anyone give some advice?
if you want to compare two dates, it is good practice to use data from the same track (relative orbit). This ensures that they have the same looking direction and incidence angle and coregistration works better. If you use SLC data you need to apply the TOPS Coregistration, but I think for your purpose GRD data would be sufficient. It is smaller in file size and some pre-processing (such as debursting) can be skipped.
Thanks for the answer I was looking for products from the same track, kind of disappointed on how much time I’ve spent trying to find them, though. The good news is that I was able to find two coincident scenes in the end. I am at the point where I wish to practice with more types of Sentinel 1 products and I have played a bit with GRD before, hence my need to proceed with the SLC data.
Anyways, I was looking for products from 2015 onwards and managed to find only one from 2016 and one from 2017, both S1A.
yes, coverage in 2015 is often very low.