The Order of DEM Creating Steps

What expression did you use to the show the differences in band maths?

elevation - elevation_VV

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I used the same expression as well, the difference didn’t appear visually distinguishable like the one appears as red areas.

Lastly, I know I’ve been too much, what is the reason for the perpendicular baseline to be negative and why does it change after coregistration?

can you show a screenshot of your data product and the difference raster?

About the second point I am not sure.

It looks like this closely;

the color table would be helpful as well. What is the range of your results?

Looks the same for me. Difference is mostly between -75m and +75m

Hi musicnerd

I found this from TM-19 ESA about baseline, I quote:

Once a ground reference point has been identified, the variation of the travel
path difference Δr that results in passing from the reference resolution cell to
another can be given by a simple expression (an approximation that holds for
small baselines and resolution cells that are not too far apart) that depends on
a few geometric parameters shown in Figure 2-2.

The parameters are:

  1. The perpendicular baseline Bn
  2. The radar-target distance R
  3. The displacement between the resolution cells along the perpendicular to
    the slant range, qs

I am sorry for the late response.

The case for difference doesn’t look same for me.

What can be the cause for it? As far as I can see, the only difference is the polarization I used. May it be the only cause?

I guess so. The trend is clearly similar to mine.

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hello,
please how to export the histogramme of coherence from sentinel 1 toolbox ?
thank you.

the whole forum is full of examples and workflows on how to do it. Just do a bit of research and you’ll find out.
The first post in this topic lists all required steps

InSAR processing with Sentinel-1 data is demonstrated here:
http://step.esa.int/main/doc/tutorials/sentinel-1-toolbox-tutorials/ (2 tutorials)

The theory behind InSAR is explained here:
http://earth.esa.int/workshops/ers97/program-details/speeches/rocca-et-al/1

If your study depends on it you should be willing to learn it instead of waiting for solutions coming to your inbox. If you have questions on specific steps, feel free to ask in here! But don’t expect others to do your research.

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I have a question in my mind with the usage of external SRTM datas.

What is the reason for SRTM DEM to be used during Phase to Elevation? And, is it only used for geocoding during Terrain Correction?

That’s the problem, I tried to make it like 100 times and every time I get an empty images, no errors appeared. I did all the steps above

If you tell us what steps you undertook and which data you used, we maybe can help you. Screenshots are always good.

I am not looking for easy solutions ! it’s my first time using snap and as u can see i am really willing to understand it ! that’s why i am posting questions all the time. May be it looks dumb to u but i am trying my best. Thanks for responding to my post but i felt offended by your words. May be u did understand me wrong. I’am only seeking for some pieces of advice and help that’s all. And i am sorry if my post bothered you

Dear @khaldi ,
My post was answering a question asked by hardbasova but it got deleted in the meanwhile. So no need to be offended - i don’t think there are stupid questions in here. Sorry for the misunderstanding.

Addressing your question: Do you want to export the values of the histogram or the image itself?

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i am sorry too. i did misunderstand it.

Is the GCPs(Ground control points) really necessary for creating a InSar DEM? I do not think so.

Have you noticed the values around the boundary areas of @janaya 's created DEM? They are quite different with the values in the core regions of the image.
There was a dividing line along the red arrow. What’s the reasons? And how to solve this problem? @ABraun

Have you noticed the values around the boundary areas of your created DEM? They are quite different with the values in the core regions of the image.
There were two dividing lines in the left and right part of your image, respectively.
What’s the reasons? And how to solve this problem? @ABraun