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esrivas17 / gacos_correction_for_GMTSAR

Atmospheric GACOS correction adapted for GMTSAR
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phasefilt.grd #4

Open zth1015 opened 1 year ago

zth1015 commented 1 year ago

As far as I know, GACOS data corrects the unwrapping phase, but your code corrects the filtering phase, which I don't understand. Could you please explain it? If GACOS correction is carried out for filtering phase, how can the subsequent unwrapping and SBAS be carried out? Look forward to your reply. Thanks.

esrivas17 commented 1 year ago

Hi, this is actually a very good question. Originally on the GACOS website, the corrections are applied over wrapped phases. So, I tried to keep it this way. The code applies the corrections over the phasefilt.grd grids, so you should unwrapped the new grids (detrended or not detrended depending on your needs) and then forward those to the SBAS algorithm. You can take a look at this file also. http://www.gacos.net/static/file/ReadMe.pdf

Thinking about this, I feel that if you apply corrections to the unwrapped phases you won't notice any relevant changes (I might be wrong though). I noticed that myself and changed the code, this was the idea I had first in mind.

zth1015 commented 1 year ago

Hi, this is actually a very good question. Originally on the GACOS website, the corrections are applied over wrapped phases. So, I tried to keep it this way. The code applies the corrections over the phasefilt.grd grids, so you should unwrapped the new grids (detrended or not detrended depending on your needs) and then forward those to the SBAS algorithm. You can take a look at this file also. http://www.gacos.net/static/file/ReadMe.pdf

Thinking about this, I feel that if you apply corrections to the unwrapped phases you won't notice any relevant changes (I might be wrong though). I noticed that myself and changed the code, this was the idea I had first in mind.

I'll try, thanks.

zth1015 commented 1 year ago

Hi, this is actually a very good question. Originally on the GACOS website, the corrections are applied over wrapped phases. So, I tried to keep it this way. The code applies the corrections over the phasefilt.grd grids, so you should unwrapped the new grids (detrended or not detrended depending on your needs) and then forward those to the SBAS algorithm. You can take a look at this file also. http://www.gacos.net/static/file/ReadMe.pdf

Thinking about this, I feel that if you apply corrections to the unwrapped phases you won't notice any relevant changes (I might be wrong though). I noticed that myself and changed the code, this was the idea I had first in mind.

Hi, I tried it, and I found that there was nothing in the script that could be changed to use the corrected filtering phase. Do you have any suggestions? Look forward to your reply.

esrivas17 commented 1 year ago

To unwrapped the new files there are a couple of "tricks" you can try. Either saving the current phasefilt.grd grids with a different name and then renaming the new files to "phasefilt.grd" OR edit the unwrapping script from GMTSAR that takes phasefilt.grd and replace with the file name you want the script takes for unwrapping (gacos detrended or whatever) .

zth1015 commented 1 year ago

To unwrapped the new files there are a couple of "tricks" you can try. Either saving the current phasefilt.grd grids with a different name and then renaming the new files to "phasefilt.grd" OR edit the unwrapping script from GMTSAR that takes phasefilt.grd and replace with the file name you want the script takes for unwrapping (gacos detrended or whatever) .

That's a possible solution. I'll try it. Thank you. I have another question for you. When unwrapping, should snaphu_interp.csh or snaphu.csh be used in unwrap_intf.csh? I noticed that there are two csh scripts of snaphu. Mine is the Qinghai-Tibet Plateau, there is no earthquake, may I ask the second value in "snaphu_interp.csh 0.01 0" should be set to what is appropriate? image