Difference between vertical and LOS displacement

Dear Andreas,

Just a question on the LOS export.
How may I export ascii file including lat lon east north and up from unwrapped interfrogram in SNAP(after importing unwrapped interfrogram from snaphu) ? I couldn’t find this subject in the forum and in the S1 manual.

Thank you.

as far as I know, SNAP doesn’t support ASCII export, but you can use gdal, for example:


But ASCII files can only contain one raster at a time, so you will have to repeat it for any information you need. Make sure you check lat/lon files and elevation in the interferogram step.


The geometric/dem bands might be lost after unwrapping but as it is the same geometry, you can use the rasters fom the inteferogram product:

Navigate to your directory:

gdal_translate -of GTiff .\elevation.img elevation_out.asc

You find similar answers here: https://gis.stackexchange.com/questions/59323/convert-geotiff-to-simple-xyz-elevation-file


You can also do this in QGIS, for example.

Thank you for your time and reply.

Is there any plugin in the SNAP to convert LOS displacement to three components (NS,EW,UP/DOWN)?

I don’t think so.

Thank you!


We could add it in the future from ascending/descending analysis.

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Dear @johngan,
The your results in LOS geometry is nice, I am new in PSInSAR technique.
Can you share for me and formun the proscessing that you run subsidence for the area of Ho Chi Minh in Viet Nam.
It is necessaryfor me and my thesis.

Thank you so much.

please have a look here: About the STaMPS category

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Thank you @ABraun
I try do this tutorial but I have problem with Step 2 (like figure).
Do you have idea to reslove this problem?

Thank you in advance.

I don’t know, sorry

Thank you ABraun

Can you debug a bit and see the value of the variables which are giving the error? As you get exact information on file and line giving the error… you may try to do some debugging.

Normally this might be due to invalid values such 0 or NaN used as indexes… so maybe you can filtering them out.

Give a try and let us know

Dear @mdelgado

Thank you your advice,
I try tocheck step by step in SNAP and StaMPS (Stamps.log), but I am not sure but I do not see 0 value or NaN value.
Can you see figure and do you have idead for this problem?

This is file about “20171113.lat.par”,



Step 2_stamps

Best regards.

This is mt_prep_snap

You should not only look at the StaMPS log. Try to load any variable such as pscands.ij or similar and search 0 or NaNs inside.

Dear @mdelgado,
I have checked pscands.1.ịj, pscands.1.da, pscands.1.ij0, but they do not have 0 or NaNs value and “pscands.1.ij0” does not value, does right?

Well, I am running out of ideas then.
Had you visually checked the interferograms to verify that all look ok?

Let us know

@ABraun @falahfakhri @johngan can you please sort out how this is done using SNAP?
Is it possible to use 20 pairs (A+B), (B+C) , (C+D) … so on which will produce separate stack for each pair and also separate interfergram. So my query is about how we can produce stack of all these interferograms at this stage for performing a time-series analysis?

Please take a look at this topic,

Thanks @falahfakhri, i read all the conversation btw u and andy.
At the end of the day we dont have any perfect methodology on which we rely.
What if we calculate the subsidence using No.of pairs (A+B, B+C, C+D, …) till last step (displacement) separately and averaged the results of all displacement layers.