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yumorishita / LiCSBAS2

GNU General Public License v3.0
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Compare GNSS #51

Open SKYNET-code opened 1 month ago

SKYNET-code commented 1 month ago

I downloaded the Gnss displacement data from the Nevada Gnss all station site and ran Licsbas for the frame mentioned in the article.  The output of the displacements of Insar is the same as the licsbas article, but the displacement of Gnss is not the same.  I moved the Gnss displacement vector according to the following formula to los.  Please tell me where is the problem with our work?  los = Vu .  U+Vn.  N + Ve.  E Vu, Vn, and Ve from GNSS U, N, and E from the LiCSBAS

yumorishita commented 1 month ago

It looks correct. How different? The difference might be from the provider; I used the data processed by GSI, not NGL.

SKYNET-code commented 1 month ago

It looks correct. How different? The difference might be from the provider; I used the data processed by GSI, not NGL.

Insar displacement does not match with GNSS.  Station j179 is the same as station 950179 of the article, and its Insar displacement is similar to the article, but different from Gnss ngl. How can i use the GSI?

IMG_20240512_005403_319.jpg

yumorishita commented 1 month ago

Did you set the reference at 950217?

SKYNET-code commented 1 month ago

Did you set the reference at 950217?

No, how can i do this?

yumorishita commented 1 month ago

Subtract the displacement at the reference. You also need to set the same reference in the LiCSBAS displacement.

SKYNET-code commented 1 month ago

Subtract the displacement at the reference. You also need to set the same reference in the LiCSBAS displacement.

I dont now how to do this, please help me.

yumorishita commented 1 month ago

What point don't you understand? How did you compute los = Vu . U+Vn. N + Ve. E? You just need to compute the double difference of 950179 and 950217. The reference of LiCSBAS displacement must be set, e.g., by --ref_geo option of LiCSBAS_cum2tstxt.py.

blueyeti1994 commented 1 month ago

I downloaded the Gnss displacement data from the Nevada Gnss all station site and ran Licsbas for the frame mentioned in the article.  The output of the displacements of Insar is the same as the licsbas article, but the displacement of Gnss is not the same.  I moved the Gnss displacement vector according to the following formula to los.  Please tell me where is the problem with our work?  los = Vu .  U+Vn.  N + Ve.  E Vu, Vn, and Ve from GNSS U, N, and E from the LiCSBAS

I downloaded the Gnss displacement data from the Nevada Gnss all station site and ran Licsbas for the frame mentioned in the article.  The output of the displacements of Insar is the same as the licsbas article, but the displacement of Gnss is not the same.  I moved the Gnss displacement vector according to the following formula to los.  Please tell me where is the problem with our work?  los = Vu .  U+Vn.  N + Ve.  E Vu, Vn, and Ve from GNSS U, N, and E from the LiCSBAS

may i know how did you read U.geo, N.geo and E.geo to multiply with GNSS displacement. I used QGIS to open any of .geo format but it is showing me error and used notepad to open the .geo file but it is giving me weird characters.

yumorishita commented 1 month ago

You should convert the float file (*.geo) to GeoTIFF using LiCSBAS_flt2geotiff.py.

SKYNET-code commented 1 month ago

What point don't you understand? How did you compute los = Vu . U+Vn. N + Ve. E? You just need to compute the double difference of 950179 and 950217. The reference of LiCSBAS displacement must be set, e.g., by --ref_geo option of LiCSBAS_cum2tstxt.py.

IMG_20240530_202903_065.jpg

The following steps were performed for station 010845:

  1. Licsbas was run, and the reference point is 950217, which is in the same direction as indicated in the article.
  2. Station 010845 was downloaded from the GSI data in coordinate_F5 format and then subtracted from the reference 950217. However, the results are different from those in your article. Our GNSS data does not match your data. Can you fully explain how your comparison was conducted? Did you apply any corrections to the GNSS data?
yumorishita commented 1 month ago

I have not applied any corrections to the GNSS data. I think something is wrong with your method, but cannot say anything else only from the image above.

This is the 10years EW displacement at 010845 with reference to 950217 retrieved from GSI's service, showing >16cm displacement and consistent with your InSAR result. image

https://mekira.gsi.go.jp/charts.html?codes=950217-010845&type=baseline&term=10years https://mekira.gsi.go.jp/index.html