[ceciliabo]

Hello,
I am super new in using this software. I am processing 29 Sentinel 1 TOPS SLC images. My aim is the deformation of a dam (so quite small area). So first of all data selection. Footprints are ok, in Google Earth everything seems fine. First thing that I noticed is at the moment of Master extraction I get “28 slave images have not been extracted”. Is it an error? Still if I click view Master, I get the image. The same message though appear when I click Slave extraction.
Real problems start at the coregistration. All the 28 slave images failed. Warnings related to cull_points. Which is weird because in other software like SNAP I managed to create the stack. So I do not think it is problem of the images per se. Maybe parameters? I have no idea.
Here attached the log file, the screenshot of the footprints and the parameters for the data selection.
Any kind suggestion? I am using the compiled version for windows (very last update).
Thank you all
Cecilia

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[periz]

Hi Cecilia,
even if you have to analyze a small target (the dam), you need a minimum number of good targets to guarantee a correct and precise coregistration. Since it’s an extra-urban area, and you are using Sentinel, I’d suggest you to increase the area you are processing.
Moreover, I see in the grabbed screen that the sw warns you about precipitations in the data of the master acquisition: you may consider to change the master image.
These considerations are general. If you would plot master and slave images, we may discover other factors.
If you want to attach mat and/or log file, zip them first

[ceciliabo]

Hello,
yes well the area that i cropped has a radius of 12km so I thought it would have been ok. I tried to change the master, but still the same. I cannot plot the images because it actually does not the coregistration. I can only see the master and the slave images one by one.
Anyway here there is the log file.

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[Yuxiao]

Hi Cecilia,

It would be helpful to check the SLC images you’ve extracted.

In FITTED folder you will find 20160311.jpg.

In EXT/yyyymmdd you will find yyyymmdd_VV.jpg for each slave image.

You don’t need to show us all. A few (but make sure you include the master) will be enough to have an understanding as a start.

Q

[ceciliabo]

Hello, thanks for the answer. Now I tried changing master (20160603), choosing one with better condition. The area is the maximum common, in order to avoid problems. Some of the images are coregisterred, some are not (18 failed out 51 slaves).
A series of warnings appear, including one that says “Reference to non-existent field ‘ra’.”.
The major parts of warnings appear in the post co registration phase, which it is I suppose because of the low coherence.
At a certain point it comes also the message “send the message above to the developer”. Is there anything I can do? what can I do better? And what about that ‘ra’? Should I simply remove those 18 slaves and keep the rest?
I attached the log file and , as Yuxiao suggest, the images.
Thank you again.
Cecilia

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[Yuxiao]

Hi Cecilia,

First of all the log is not the correct one and there’s no info in the one you attached.

You can check the site.log and send it to us.

Second, there’s upload error for jpegs due to upload errors. Either send it to us in email (that is in your message) or use a cloud upload like wetransfer.

Then we will try to get a better understanding with that.

yuxiao

[ceciliabo]

Hello!
So this is the link of the files, and hopefully it works. If you need something else, please do not esitate.

https://wetransfer.com/downloads/7e2f5bf6078bee04c505b436cb072a6c20170611180039/fd2be1f1e309a56f7a59363054107e4520170611180039/94c347

thanks

[Yuxiao]

Hi Cecilia,

Sorry for the late reply but we are still investigating the multiple errors in your case.

Meanwhile, I will need some more files from you.

In the folder where you placed your sarproz.exe, you should be able to see multiple files with the name “lasterrorS1_yyyymmdd_yyyymmdd.mat”. Please send them all to me. You can do so either with wetransfer again or email me at qyuxiao@sarproz.com.

we will get back to you asap.

Q

[geoalicia]

Did any solution came from this post? Im facing the same problem cull points:fewer than minimum points

[Yuxiao]

Yes. We closed this issue but forgot to post the solutions here.

There were several errors/messages mentioned in this post. Which one exactly are you getting?

We have fixed all the errors that were discussed in this post, so the first thing is to make sure you have the newest version of sarproz.

Then please let us know which error you are getting. It would be nice to include logs.

yuxiao

[geoalicia]

I m having error “cull_points: fewer than minimum points” in 15 images. Im using the version 18-sep-2017, my master image has no rain/snow and and area of 20km radius, also already try orbit and coarse xcorr. co-registration but with the same outcome error

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[Yuxiao]

Hello,

It would also be nice to see the jpeg image of the master in your FITTED folder. Could you share that as well? You can upload the jpeg file to wetransfer and paste the link here.

yuxiao

[geoalicia]

Sorry for the delay, but I want to make 100% sure what was going on. From what you suggest I could find a shift in my images, they all cover my area of interest, however the select area in sarproz area selection option and the area of the master images are different!
The link above contains: master image in jpg, the log file and an explanation image (in google earth of where is the area of interest and where the master is selection the area.
note: I also use other images as masters, but the mistake persist.

http://mysharegadget.com/570476040

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[Yuxiao]

Hello Alicia,

I would check the following as a start: the extracted master and slave images. In the attached file you showed me, I can only see the jpeg of master image. Could you also show me a few examples of the slave images? You can find the corresponding jpeg images in the EXT/yyyymmdd folder.

I can see that the master area extracted is corresponding to the yellow polygon in the figure you appended. But I could see anything for the slave images. That’s where we should start our investigation.

Please let me know. Be free to ask any questions at any time.

yuxiao

[geoalicia]

Hello Yuxiao,

The slaves images are also in the wrong location, just as master, even if the location coordinates dont belong there. From 24 slaves, 22 didnt corregistrated and 2 did (even in the wrong spot). In the link 2 images with no errors in date 04-jan-2016 and 03-may-2016; two with errors 22-mar-2015 and 15-04-2015.

The interesting thing is that if I use both years 2015 and 2016 as different analysis this problems dont happen.

http://mysharegadget.com/279553746

[Yuxiao]

Hello Alicia,

I suggest we set up a remote session for me to take a look at your dataset. Are you familiar with using teamviewer?

In this way, we could quickly go over your dataset and diagnose the problem.

If you have teamviewer installed, then email me at qyuxiao@sarproz.com so that I can quickly connect and see the dataset.

yuxiao

[Yuxiao]

Just to note here that this issue has been solved.

For other’s reference, when one is importing SLC data:
1. Check if the input latitude/longitude is consistent with the MasterArea.kml (that is generated by clicking “View”);
2. Check if the extracted Master image is corresponding to the MasterArea.kml (you can see the master image by “View Master”);
3. Check if all extracted slave images corresponds to the MasterArea.kml (“View slave”)

After all are checked, one can start doing coregistration. It is generally advised to use a bigger area to coregister a heavily vegetated area. If coregistration fails, please firstly search in the forum to look for general advice that will make coregistration work.

yuxiao

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