Gpt hangs during polarimetry graph

[sandersson]

Hi,
I’m running a single graph of polarimetric decomposition on Sentinel-1 scene using gpt.

The command hangs once the processing is part complete (1/3 judging by this image) with no error message.

I am using SNAP 5 and have allocated around 24GB RAM to gpt.
Any help would be appreciated! For now I will test a different scene.

[MCG]

Hi @sandersson

If the process has been killed, you should see some message from gpt. Can you try again and post a screenshot of GPT?

M

[sandersson]

Should yes, but in the end it just hangs and it doesn’t say why it stops processing.
Thanks,
Simon

[MCG]

I just see that it is using restituted orbits instead of precise orbits. Update SNAP to version 6 and try to run the graph again, let’s see.

M

[sandersson]

Updated to SNAP 6.
Graph gets to 20% and says ‘Database closed’ and then hangs.

No error message. My intuition says it’s a resource issue but there seems to be enough space and RAM, plus the graph works in the GUI.

Frustrating because I am running a service based on automated SNAP processing with gpt, and I think this is a bug created by the Sentinel-1 format change!

See also:

GRD-Border-Noise and Thermal noise removal are not working anymore since March 13. 2018

I’m also having issues with GPT at the moment. I have a polarimetry workflow that works in the SNAP GUI but not in GPT. GPT gives no errors but hangs so I assume it’s a memory issue? Maybe there is a better way to debug GPT (I will try with -e). My machine has 64GB RAM and I have allocated up to 40GB.

ESD NullPointerException

Hi, I am trying to corregister two Sentinel-1 SCL products with ESD. I have tried the process in three different ways: step by step, using the Graph builder, using the S1 TOPS Corregistration with ESD tool. However, the step-by-step method fails at ESD with following error: org.esa.snap.core.gpf.OperatorException: java.lang.NullPointerException at org.esa.snap.engine_utilities.gpf.OperatorUtils.catchOperatorException(OperatorUtils.java:432) at org.esa.s1tbx.sentinel1.gpf.SpectralDiversi…

[sandersson]

The steps in the graph are:

1. Read
2. Apply-Orbit-File
3. TOPSAR-Deburst
4. Polarimetric-Matrices
5. Polarimetric-Speckle-Filter
6. Polarimetric-Decomposition
7. Terrain-Correction
8. Write

Again the graph works in the SNAP GUI but not in the command line. Perhaps someone could test the graph ?

When I use “gpt -e” the graph hangs at just past 20% processing.

Regards,

[sandersson]

Resolved by calling gpt with the -c parameter set at 75% of the java heap space.

eg:
“gpt -c 24G”

The java heap space is set using -Xmx in gpt.vmoptions.
This has also reduced the time for my processing chain to run by a factor of 4

gpt --diag was also helpful.