I have stumbled upon a bug where the tile size affects the computation results of S-1 TOPS Coregistration.
The data sets used are named:
From the coregistration options we are using subswath IW1 with a polarisation VV. Also we are masking areas with 0 elevation and using bilinear interpolation.
elevation model is srtm3.
if snap uses default tiles which should be about 500x500 then the pixel (6251;6186) is valued as 0 or NaN as it is masked out.
If I am forcing larger tiles such as a 2666x1500 tile, then some coastal areas start to differ. It seems that elevation mask is not applied at some areas. Particularly pixel (6251;6186) and its surrounding area.
The exact tile that troubles me is x:5332 y:6000 w:2666 h:1500.
When I remove masking, then the pixel is valued very close to what it is valued on tile x:5332 y:6000 w:2666 h:1500 with the first difference occurring on the 3rd decimal place.
Previously when working I have noticed that coastal areas have differing results also with small tiles such as 100x100.
Is this a known issue? Is this functionality intended? How do I define what is the correct result in this case?