Wrong polar-type argument in config.txt when data exported from snap was imported to PolSARpol

We precessed two-date Sentinel-1 SLC. The processing was described in the literature as shown below(Mandal et al., 2020).

After the step of Stack Split, one-date Sentinel-1 image was shown as below.

Then export to PolSARPro format as shown below.

There was a fatal error when we imported this data to PolSARPro. The error message was that there was wrong polar-type argument in config.txt. But the dual polarazation of Sentinel-1 is right. Moreover, there is no error in the precessing. We cannot find the reason.

1 Like

I’m not sure if PolSARpro likes manually preprocessed S1 data. Is there a reason why you don’t use version 6?

1 Like

I have used PolSARpro 6.0. But there is the same error. :joy:

Can I ask again why you don’t load the raw data into PolSARpro and select the swaths/bursts there?

Because we want to follow the preprocessing flow as shown below.

Until which step of this graph did you pre-process the data in SNAP before loading them into PolSARpro?

Maybe it is a good idea to contact the authors of the paper on how they managed to bridge SNAP and PolSARpro?

We precessed the data in SNAP before DpRVI generation. It is a goog idea to contact the authors of the paper. Thnaks.

After contacting the authors of the paper, PolarType in config.txt should be ‘full’ instead of ‘dual’. Moreover, C11, C22, C12real, C12imag, and config.txt should be within ‘C2’ subdirectory. Then the data can be imported to PolSARpro.

1 Like

very good, thank you for sharing this.

This means that the data exported from SNAP

  • has “dual” written in the config.txt instead of “full”
  • has the config.txt in the wrong directory?

I think this could be fixed with little efforts by the developers.

I second this.

When exporting partially polarimetric S-1 data into PolSARpro format, config.txt gives PolarType = dual, when it should be pp1, pp2, or pp3 depending on the product.

@hiny I’d love to see this paper. Could you kindly make reference to the full paper title or give the doi?

Thanks in advance!

The full paper title is ‘Dual polarimetric radar vegetation index for crop growth monitoring using
sentinel-1 SAR data’.

Thank you for the full paper title. Interestingly, the workflow figure you provided and that from the paper are different.

Could you tell me the difference?


retrieved from:

The worlflow figure I provide is retrieved from:
Dual polarimetric radar vegetation index for crop growth monitoring using sentinel-1 SAR data.pdf (1014.6 KB)

I see. Thank you for providing the published version. It appears the authors made some adjustments based on review comments.

Section 3.1. of this paper does a great job at explaining exactly what is required for getting the required binary outputs for PolSARpro. Initially, and as this paper subtly shows not to do, I was using ESD after back-geocoding, a step I thought was required based on several conversations and videos I’ve watched (people always say it’s a “two step” process). At least for me, for some reason, ESD doesn’t play nice when the goal is exporting to PolSARpro format. I omitted it and it went smoothly afterwards. I thought I would mention this in case someone else has the same issue.

Perhaps someone out there knowns why ESD might prevent the export of PolSARpro binary files???

@hiny Are there any other small quirks you may have encountered when importing the C2 PolSARPro matrices exported from SNAP? Every time I try to import those matrices as either Single Data Set or Multi Data Sets, I get:

Where you successful in getting past this?

In our test, ‘D:\TEST\topolsar\S1A_IW_SLC__1SDV_20190608’ is the main input directory.

1 Like

That did the trick. Thank you!

We should be pointing to a directory containing C2 rather than pointing to C2 directly.