DEM generation

hi, as i understand, you should use “phase to elevation” operator.

Please take a look at this topic answers your question.

Hi @ABraun
i made a DEM in SNAP and convert it to GeoTIFF format . i intend to use this file in ArcMap. based on fig below, how to remove black borders (No data value) from this DEM?

Thanks you :slight_smile:

you can define a NoData value in ArcMap directly in the symbology tab. Check the box and all 0 values become transparent.

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Thanks for quick responding. i did this earlier, but it didn’t work for me. i also tried with the procedure that is mentioned in fallowing website:
but it didn’t work too.

What value is the black area in your raster?

Do you have the tutorial or website link about how to do SNAPHU Unwrapping. Now I have no idea about this step.
I have been working with images of Sentinel 1A IW SLC and I have done coresgistration, interferogram formation, deburst , topographic phase removal and phase filtering.


Maybe you can use the raster caculator tool in ArcGIS to extract the values greater than 0 firstly, then convert the reasulting image to ploygon and output the polygon with 1 value. After doing this, just clip the DEM by using the polygon file covering your study area.

Hope any help to you.

I’m pretty sure the black areas can be set as transparent in ArcMap with a few clicks.

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Thanks. Your tutorial is so helpful to me. Now, I have gained a better understanding about the Unwrapping.
To do the Unwrapping process, I adopted the following 3 steps. First step : Radar>Interferometric>Unwrapping>Snaphu Export, the menu in SNAP software. Second Step: create the unwrapped phase by snaphu, an external program which runs by command line. Last Step: Radar>Interferometric>Unwrapping>Snaphu Import, again in SNAP software.
Is this the correct order for Unwrapping ? @ABraun

Yes, this is correct.

I do it like what ABraun said.

I need to calculate the vertical baseline between 2 Sentinel-1 aquisitions,
Please, can you help me?

thank you

You can use the InSAR stack overview tool

In addition to steps listed above, does there other optional steps in order to improve the the height accuracy of the generated DEM? using SNAP

  1. Corregistration by using the function “S-1 TOPS Corregistration” (Sentinel 1 Toolbox)
  2. “Interfarogram Generation”. In this step I’m considering the corregistered IW Swath;
  3. deburst
  4. “Goldstein Phase Filtering”;
  5. “Snaphu Export”. I’m not applying the topographic phase removal, since I’m interest in the resulting DEM and not DinSAR,
  6. “Snaphu Import” of the unwrapped phase;

Accordining to the Nest turtorial for Etna, I used:
7. Interferometrix-Products- PHASE to height
and Range-doppler creation.

1- Large Bperp
2- Consider Topography area
3- Coh
4- ascending and descending

I follow these steps but getting Problem in Snaphu import but when I apply phase removal than there is no problem, but I want to generate DEM of my study area what should I do?

did you select the HDR file?

What is the “.snaphu” file in your product? Seems like you calculated it with band maths.

No, I select the .img file in unwrapped phase.
.snaphu is unwrapped file and I did not use band math till now.
I did unwrapping in Snaphu in linux . it working properly when i use unwrappe phase (which i get after topographical phase removal)but when I did filtering after Deburst and than Snaphu Export and import getting problem above mentioned.