SNAP Error: [NoteId: Subset] Operator ‘SubsetOp’: Value for ‘Source Band’ is invalid

Is it possible that I downloaded strange data or processed it incorrectly? It’s a shame that I do everything according to the tutorial, but there are mistakes that just confuse me at all

I noticed that you were working with products [1] and [2], but my tutorial at this stage already uses products [3] and [4], which were pre-processed by the following graph (screenshot 1 and screenshot 2, respectively)


It would have been good to know this from the beginning actually :wink:

I applied the same preprocessing and did not encounter any error.

oh, you did it without subset. does this have any effect on the result?

this time I did not include the subset, but I don’t think that caused the error. Please try to create the graph from scratch.

so i delete subset operator and process has started.

I’m very sorry to bother you with such simple questions, but can I ask you for help inside this topic if needed?
ahead of me is one of the most incomprehensible moments where I have an error “The specified region, if not null, must intersect with the image’s bounds” and I’m afraid that I can’t solve this issue, even using EXACTLY THE SAME DATA as in the tutorial (now I’m trying with my territory)

Have you tried SAR Simulation Terrain Correction instead of Range Doppler Terrain Correction as I suggested here?

I get the feeling that you are following the steps without understanding their purpose.

Especially when you experience many errors, it is often better to execute the steps separately and not as a graph. Otherwise you never know at which step the error occurs. Also you have no control about the contents of your data.

Applying graphs is great to automate processes for repeated use. But for single studies I see little benefit from it.

I tried. at first, the process took 2.5 hours, after which I received a file (or product [7]) that weighed extremely much and did not contain any data. For example, in the tutorial it was written (screenshot 1), but I didn’t have any data, there was nothing to move, everything was equal to zero. Although the vector grid was present, I still don’t understand why it doesn’t work with Range-Doppler Terrain Correction.

have you checked if the velocity raster looks alright before terrain correction?

I got the following, I’m not sure if this is normal, but I don’t know how to fix it. anyway, it was with the past data. I was very confused when I downloaded exactly the same data as in the tutorial, published it and strictly completed all the tasks, and there WAS EXACTLY THE SAME ERROR.

sorry for the caps, I just don’t understand what the reason is…

looks alright, besides of the error tiles. Maby a lower azimuth/range spacing would improve the result.

Have you selected the Velocity band as input in the terrain correction?
It is very hard to me to understand the differences between the RUS tutorial and your personal workflow. Maybe there were minor differences but I cannot see them.

I don’t see it either, I do everything exactly, but if something goes wrong, I’ll try to redo it a few more times.

this can’t be related to RAM? I have 16 GB of RAM, but I don’t know if that’s enough.

16 GB is sufficient for GRD products

If you are working in a different area, the only thing that changes is the UTM zone.

Maybe you should not stick too much to the tutorial and simply follow the steps that make sense to you. Also, not as a graph, but process one product after the other.

I’m ashamed to say, but Yes. The tutorial that I found is the initial stage of my diploma, I am doing all this for the first time and for the first time I see all these operators and start these processes.

Maybe you first need some basic understanding of SAR pre-processing to undestand the purpose of all steps:

Alternatively, you can try to follow the Offset Tracking tutorial by ESA:

Starting with the graph builder is probably the worst thing you can do as a beginner, because it keeps you from following the different steps. Checking the outputs of every step is crucial for a basic understanding.

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I will definitely look and try to reproduce what you sent with your data. It doesn’t matter what data I take, does it?

And one more question: I found the help for SNAP, which tells about each operator and the mechanisms of action. Can I find a solution to the problems there, or are these just general explanations that need to be shown in practice?

The help is suitable to understand what each module does, but it’s not helping in case of errors.
The error messages are often generic and not always pointing at the source of the error. So its always preferable to know what is done and why.

thanks a lot! I really hope that after studying the materials, I will have fewer problems, but if something happens, can I share it here or is it better to create a new topic?

Please try to find a suitable topic with the search function where your new questions fit in best. Either based on the error message (check the suggested solutions as well) or the application (offset tracking).

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okay, thank you again!