Apply orbit file problem

Hi all

When I’m trying to apply an orbit file to a sentinel-1 image (happens with either split and non-processed images), this error appears:

image

The data I’m using is downloaded from the copernicus open acces hub and is still unzipped (like indiciated in this tutorial). The process worked perfectly fine last week, but now SNAP keeps throwing me this error. When I check the “do not fail if new orbit file is not found” box, the subsidence mapping process just fails further down the line.

Could it be that there is a general problem with SNAP at the moment or am I overlooking something?

Thanks in advance and kind regards
Lennard Derudder

this soulds to me like the product was not completely downloaded.
Have you tried opening one of the bands to see if the input product looks alright?

As far as I can see, the input data looks alright. But it should be allright because it is the same input data I used last week when it did work.

sorry, I’m still not clear about your error.

What happens when you want to apply TOPS Split on the data? Same error message?

Can you please specify this?

Okay I’m maybe a bit unclear as to what I’m trying to do. I’m trying to see how much land deformation has been happening in a certain area and for that I am using Sentinel-1 imagery. When I open the images in SNAP, everything looks alright (I’ve checked the bands and the quicklook files). Now, my initial question was about the orbit files, but I seem to have solved that problem by uninstalling SNAP a few times and installing the updates untill the error didn’t show up anymore. I only specified that problem initially because I thought it would also solve the other problem I encountered further in the process, but it apparently doesn’t.

The problem I’m now facing is when I’m trying to use SNAPHU Unwrapping

Everytime and without fail, the process aborts at the 11th “Unwrapping tile at row…”. I have changed the number / overlap of rows / columns numerous times in the SNAPHU Export, but they all yield the same result. Here you can see the workflow I’m using in the Graph Builder

Is there maybe something wrong with the Graph? Or do you think the problem is situated elsewhere?

ok, thank you for explaining it. Good to hear that you have solved the orbit issue.

If the unwrapping fails regardless of the tile size, my first question would be if the filtered and subsetted interferogram looks alright after processing it through this graph. Can it be unwrapped? Interferograms which are only phase noise potentially lead to aborts in snaphu.

Also, please delete the tile folder every time you re-run snaphu.

If the interferogram looks okay, you can switch to an MST solver instead of MCF (no need to re-run the graph, simply modify the snaphu.conf and delete the output before you run it again.

I think I managed to solve the problem by not implementing the SNAPHU Export in the Graph Builder because I discovered that I was unable to choose the BEAM-DIMAP file format within the Graph Builder, but that was necessary for the SNAPHU Unwrapping to work. I did delete all the SNAPHU files everytime I reran it so that couldn’t have been the problem.

At the moment the unwrapping is still running, but if you don’t see another answer popping up from me on this thread, then it means that everything is finally running just fine.

Thanks for your time!

good to hear. Using graphs is handy when you have to repeat the same task multiple times, but you lose control over the different parts along the processing chain. Especially when errors are happening at one step you end up with an empty result but don’t know at which point the problems started.