Segmentation Fault on Fraction of Green Vegetation?

snap Sen-ET
#1

I’m trying to run the Fraction of Green Vegetation Operator, but the it just returns a Segmentation fault with no further explanation. Has anyone managed to get it to work?

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The inputs (BIOPHYSICAL/ZENITH) I’m using can be found here:
https://drive.google.com/drive/folders/1e0Hdpfi9m1QDgXkmKz_HWRcj3Y8OreJn?usp=sharing

Is it possible to set a verbose flag or something for these operators to show more info on errors?

Thanks.

#2

I am also facing the same issue. Please let me know if you got any solution for this.

#3

Unfortunately not. I made an effort to try it in several ways, and this plugin never worked. There was always an error or a problem.

#4

@radosuav Can you please explain this?

#5

Sorry but cannot help much here. Segmentation fault is usually related to memory or disk access problems. Have you tried on another machine?

#6

Ok thanks, will try that.

#7

@radosuav did you see @napocornejo’s zenith_angle product, the sun_zenith band is within a sub band sun. My data is also similiar.
Is that fine?

#8

@radosuav Tried with other machine with the following configuration:

  1. SNAP 8.0 Configured with python3.6

  2. SEN-ET 1.0.1

  3. UBUNTU 20.04

  4. RAM-32GB, ROM-256GB

Still getting the same error. What else you will suggest to do?

#9

The location of sun_zenith band looks fine, that’s where it’s located within S2 L2A product and the location is kept when using SNAP subset operator.

I am not sure what could be causing the segmentation fault. Python code used by this operator is fairly simple so I don’t think that this could be the cause. That leaves file I/O for which snappy is used. The plugin was developed and tested with SNAP 7. Maybe something has changed between SNAP 7 and SNAP 8 in the way that snappy should be used. Could you try installing SNAP 7 (you can get it here) to check if that works?

#10

@radosuav sure, I’ll try with SNAP 7 and SEN-ET 1.0.1.

#11

@radosuav Tried with snap 7.0 and SEN-ET 1.0.1 .
SNAP is configured with Python 3.6.13 and compiler used is GCC 9.3.0.
Still getting the segmentation error. What to do now?

#12

Hi @marpet and @ABraun ,
Can you please suggest any solution to overcome this error? I am not even sure if the error is from SEN-ET plugin side or from SNAP side.

#13

I’m afrait we’ll have to wait for someone who is more familiar with this plugin. As this is an external one, we cannot provide support for it. At least I don’t know what caused the error. Are you sure the plugin was installed correctly? For example, did other functionalities of this plugin work before?

#14

Yes @ABraun , I tried it around 4 months ago and was able to run each steps correctly and got the final output.
This time also I’m able to run another function called "leaf reflectance and transmittance estimation.

#15

maybe your input data is different from the last time?

#16

Let’s try to find the place where the segmentation fault occurs. Can you edit frac_green.py in <USEPROFILE>\.snap\auxdata\sen-et-conda-Win64\sen-et-snap-scripts\ and put some print() statements in (e.g. on lines 15, 21, 39, 42).

1 Like
#17

Ubuntu 20.04 provides Python-3.8, so it is important to tell us which Python-3.6 you are using (Anaconda, deadsnakes ppa, or ??).

#18

Hi @gnwiii I created a conda environment with python 3.6 and then configured with SNAP. Then check the python configuration which is running perfectly.

#19

Yes @ABraun The data location is different but same Sentinel 2 L2A data is used.

#20

You could get a segmentation fault in a python import library (due to different compiler runtime libraries) if the conda environment is not active.