[steffan]

My apologies. Here are the files.

Best

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[steffan]

Dear friends,

I have good news and bad news…

Good news – Using “orbits only” coregistration parameter not only made coregistration much faster but also corrected the failed interferograms from before, excelent!

Bad news: There is still ramping, mostly in azimuth, and strange results.

A – First the ramping pairs:

B – Now the pairs with what appears to be burst discontinuity:

C – These pairs seem to have phase shift between what I believe is a river (will confirm), which is quite strange. I’m not sure what could cause this… Could it just be an anomaly?

D – Finally here are two interesting images. Could this be due to loss of coherence? Displacement? Or a problem with interferometry? Fringes are all over the place. It would be great if someone with more experience than me could explain this type of phenomena.

By the way, I did not delete previous inteferograms from the folder, as I assumed SARPOZ would OVR the old data when reprocessing.

Thanks for the support as always,

Steffan

[steffan]

Dear Yuxiao,

I have sent you the site log file to the provided email address.

In the meantime I will check out “orbits only” coregistration.

Thanks!

[steffan]

So I re-cogistered the dataset (I know I didn’t have to, oh well) and increased the number of reference points to 500K. Didn’t notice any errors except S1_Stitching like before. Using Max Area for AOI selection.

Then I changed to MST graph I processed Interferograms. There still seems to be a lot of problems…

Ramping in numerous images, here are some examples:

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Also this problem in over 20 images! Seems like a fail in interferogram formation.

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And finally, some interesting results from others… Not sure if movement or just more errors…

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I know you said to remove pairs with problems, but at the moment that would be half my dataset!

Sorry for the long post, and thank you for the help.

[steffan]

So for APS estimation with 130+ images I can reduce amp. stab. thresh to much lower levels? I will try something like .75 and see what happens.

The only coregistration errors I got were S1 Stitching erros, which I inquired in another thread and was told to ignore. I will try coregistering the dataset again and see if there are any errors on those particular looks with bad APS.

Thank you for your support as always.

[steffan]

Hello friends,

I followed the tutorial by Mr. Yuxiao very closely. Results seem much better than before, but there are still a couple of anomalies.

First, the resulting points from 0.85 thresh amp. stab:

Coherence Before:

Graph Coherence;

Parameters Plot…

Heights:

Displacement:

Coherence after weighting (0.8; 0.95)

Coherence after APS removal:

Coherence after Graph Inversion and APS removal:

There appears to be some problems with coherence, but this is a 3 year timeline over a very large (1 subswath) rural area, maybe it is understandable? Also, do these atmospheres look normal?

Final coherence graph:

Results
MASK: Amp. Stab. Index 1-Sigma/Mu > 0.70

This looks much better now! I believe the culprit for extreme displacement was the refence point… Still there are suspicious PS’s on NW coastal area, lots of orange (-5 mm) subsidence there.

A close up of the city:

And finally a subsiding PS (albeit with about 0.5 temporal coherence)

Can I trust these results or do params need tweaking?

Thank you for your support.

[steffan]

After reprocessing the point of interest with 135 images, the results are the same (extremes of displacement).

Here are examples:

Here are APS parameters:

Maybe this time series can provide some insight:

Thank you!

[steffan]

Thank you Yuxiao

[steffan]

Dear periz,

I am reprocessing the dataset with 135 images (from 60 previous), I will post the results soon.

Thank you

[steffan]

Thank you!

[steffan]

For anyone having the same problem, selecting an appropriate manual GCP seems to fix the problem. Roads and other landscape features are properly aligned now. I used a floodlight from a football field and it seems to do the job just fine.

The all zero error seems to be due to ocean, as the satellite data does cover some coastal area.

Thanks for the help.

[steffan]

I am now getting an SRTM error:

sel_par: neither file D:\SNAP\Beja\Beja_SAR\SLC\2017\RESULTS\DemSynt nor D:\SNAP\Beja\Beja_SAR\SLC\2017\RESULTS\DemSynt.mat found

files D:\SNAP\Beja\Beja_SAR\SLC\2017\RESULTS\DemSynt and D:\SNAP\Beja\Beja_SAR\SLC\2017\RESULTS\DemSynt.mat not found

leggi_srtm: Warning! file D:\SNAP\Beja\Beja_SAR\SLC\2017\..\SRTM\N05W033.hgt is all zeros!!

leggi_srtm: Warning! file D:\SNAP\Beja\Beja_SAR\SLC\2017\..\SRTM\N05W032.hgt is all zeros!!

leggi_srtm: Warning! file D:\SNAP\Beja\Beja_SAR\SLC\2017\..\SRTM\N04W033.hgt is all zeros!!

leggi_srtm: Warning! file D:\SNAP\Beja\Beja_SAR\SLC\2017\..\SRTM\N05W033.hgt is all zeros!!

leggi_srtm: Warning! file D:\SNAP\Beja\Beja_SAR\SLC\2017\..\SRTM\N04W033.hgt is all zeros!!

leggi_srtm: Warning! file D:\SNAP\Beja\Beja_SAR\SLC\2017\..\SRTM\N04W032.hgt is all zeros!!

leggi_srtm: Warning! file D:\SNAP\Beja\Beja_SAR\SLC\2017\..\SRTM\N05W033.hgt is all zeros!!

leggi_srtm: Warning! file D:\SNAP\Beja\Beja_SAR\SLC\2017\..\SRTM\N05W032.hgt is all zeros!!

leggi_srtm: Warning! file D:\SNAP\Beja\Beja_SAR\SLC\2017\..\SRTM\N05W033.hgt is all zeros!!

leggi_srtm: Warning! file D:\SNAP\Beja\Beja_SAR\SLC\2017\..\SRTM\N05W033.hgt is all zeros!!

leggi_srtm: Warning! file D:\SNAP\Beja\Beja_SAR\SLC\2017\..\SRTM\N05W032.hgt is all zeros!!

An error occurred and was saved in the file lasterror.mat, directory C:\SARPROZ\compiled_2018-02-27 (1)

If you need assistance, please include the file lasterror.mat

You may include also file 26_Mar_2018_17_53_35_sarproz.log

Here a glimpse:

Error in findtime(): iteration did not converge!

[steffan]

I will try to select a different GCP than the auto GCP option. What are the best practices for GCP selection at Sentinel 1 resolution? I am aware posts are good for higher res. sensors, but what about ST1? A building?

[steffan]

Hi carolina,

Did you follow the tutorials available on the site? If you want to select a small area, go:

1. Select Area -> View Refl. Map

2. Now zoom in to the area of interest in the new image window

3. Once you have it in the field of view, press the Grab Area button

4. The values should be automatically input in the boxes, now press Load

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