Furthermore, the following is the kmz of coherence, there is no shift, but take a look how it looks like, (processing two burst, however, when processing one burst with the same DEM the kmz has a big shipt).
Dear Falah… I think this unwrapping error and I tried more time to overcome this problem, try to repeat the unwrapping process with different tile and if your images size with about 5000 pixels you can unwrap with 1 tile in rows and columns.
I have a question to you, I tried to generate DEM from Sentinel 1 different images, but my best images with coherence more than 0.7 but all my results with elevation less than my study area elevation about 100 to more than 200 m. As shows in followed picture one result
Dear Falah, thanks so much for your reply… I read all your source mention before and also I follow most your post here and download your PHD thesis, it is a great job…
I think it is not phase jump because it does not appear in phase image and I apply ESD but I told you it was wrapped error for with change parameter in unwrapping process I can overcome this error.
For SRTM, I don’t compare resulted in DEM with SRTM only, but I compared with most free available DEM such as ASTER v.1, v.2 and v.3, SRTM v.3 with 30 and 90 m resolution and also ALOS 12.5 m All have closed average elevation only DEM generated from S1 with very different elevation. I think there are losses rings in my processes or in SNAP software at issue of DEM generated while not the problem in deformation processes.
Finally, I will more and more try to find the problem, thank you, Dr. Falah, for all your advice to me, or to all the people here and sorry for bad English written.
Dear Falah, InSAR stacks tool don’t work with coregistration of Sentinel-1 SLC-IW product why ? While it works with coregistration of ALOS-PALSAR product? It work with sentinel-1 only after I split and deburst my two images and then coregistration with GCP point , that right ?
These are the right steps of ALOS-PALSAR coregistration and creating interferogram,
1- Select the HH or VH, or both polarization
2- Coregistration (one pair and one stack with multiple images)
3- ALOS Deskewing (for the ASF/SSARA data)
4- Interferogram Formation
5- Coherence Estimation
6-Goldstein Phase Filter (on Ifg)
7-Topographic Phase Removal (SRTM 1sec)
Thank you, dear Falah, for all your answer …and I read most post here about this matter and also your P.HD thesis.
I know about ALOS-PLASER and don’t have a problem, but I want to ask you how I get co-registration accuracy for Sentinel -1, as you see here I apply coregistration for TOPS with ESD but you go to InSAR stack tool in SNAP v.7 I can’t found co-registration accuracy values
The image pair has a temporal baseline of 12 days and perpendicular baseline of 170 m. Unfortunately, that’s the only pair I have that satisfies the 150-300 m perpendicular baseline requirement for DEM generation. There is no 6-day pair available also. My AOI is within 2 subswaths (IW2 and IW3). I’ve merged the 2 subswaths after the ‘coregistration and interferogram formation’ process (i.e., BG–>ESD–>IFG–>DEB).
Here are some additional information after the coreg and ifg process.
Goldstein Phase Filtering
-Adaptive Filter Exponent: 1.0
-FFT Size: 64
-Windw Size: 3
-Statitical-cost mode: TOPO
-Initial method: MCF
-Number of Tile Rows and Columns: 20
-Number of Processors: 4
Row and Column Overlaps: 200
Tile Cost Threshold: 500
I tried to lower the number of tile rows and columns (i.e., 5 and 1) few days ago while waiting for your suggestion but it always returns an error. I am stuck with 10 for both. I am relying now on the statistical-cost mode and initial method for the improvement if there is.
I’m trying to generate DEM in Snap software with Cosmo SKYmed images.
My datas have three difeerent temporal baseline (short, middle and long time).
I have made all processing step for DEM generation (coregistration-interferogram-goldstein phase filter-snaphu export-snaphu import-phase to elevation-range doppler terrain correction).
When I produced DEM, image have 2 bands (elevation and elevatin_VV).
1- Which is real InSAR DEM? I think “elevation_VV” isnt it?
2- When generate DEMs for all data, short baseline data have avarage 27 m error from my real DEM , in addition, other datas elevation_VV bands have so irrelevant values. Do you think what is the problem ?