SEVERE: org.esa.snap.core.dataop.dem.ElevationFile: error in opening zip file

Microwave Toolbox
#1

Hello,

I noticed that when using gpt in the latest version of snap I am running into the following error when doing terrain correction:

SEVERE: org.esa.snap.core.dataop.dem.ElevationFile: error in opening zip file
INFO: org.esa.snap.core.dataop.dem.ElevationFile: http retrieving http://step.esa.int/auxdata/dem/cdem/cdem_dem_073H.tif.zip
SEVERE: org.esa.snap.core.dataop.dem.ElevationFile: error in opening zip file
SEVERE: org.esa.snap.core.dataop.dem.ElevationFile: error in opening zip file
WARNING: org.esa.snap.core.dataop.dem.ElevationFile: http error:http://step.esa.int/auxdata/dem/cdem/cdem_dem_073H.tif.zip on http://step.esa.int/auxdata/dem/cdem/cdem_dem_073H.tif.zip
INFO: org.esa.snap.core.dataop.dem.ElevationFile: http retrieving http://step.esa.int/auxdata/dem/cdem/cdem_dem_073L.tif.zip
SEVERE: org.esa.snap.core.dataop.dem.ElevationFile: error in opening zip file
WARNING: org.esa.snap.core.dataop.dem.ElevationFile: http error:http://step.esa.int/auxdata/dem/cdem/cdem_dem_073L.tif.zip on http://step.esa.int/auxdata/dem/cdem/cdem_dem_073L.tif.zip
INFO: org.esa.snap.core.dataop.dem.ElevationFile: http retrieving http://step.esa.int/auxdata/dem/cdem/cdem_dem_073M.tif.zip
…

Looking at the urls it seems that there should be another directory in the paths to the zip files. Is there a recommendation for solving this issue?

Thank you and very best regards,

#2

Probably it is our server, which is too busy. If you try later it might work.

#3

Hello,

Though I cannot access it now, earlier in the day going to

http://step.esa.int/auxdata/dem/cdem/

did not show any .tif.zip files, but rather a set of numbered subdirectories like

http://step.esa.int/auxdata/dem/cdem/073/

which then contained the .tif.zip files the program was looking for. So it looks like the program is looking at the wrong path:
http://step.esa.int/auxdata/dem/cdem/cdem_dem_073M.tif.zip
instead of
http://step.esa.int/auxdata/dem/cdem/073/cdem_dem_073M.tif.zip
?

Thank you,

Thomas

#4

Ah, okay. Didn’t know.
@lveci @oana_hogoiu can you both check what is going on?

#5

Hello Thomas,

Just as a workaround for your specific gpt, can you try updating
DEM.CDEM_HTTP = http://step.esa.int/auxdata/dem/cdem/
to
DEM.CDEM_HTTP = http://step.esa.int/auxdata/dem/cdem/073/
inside snap.auxdata.properties (within snap installation folder) ?

Regards,
Oana

1 Like
#6

Hi, I have downloaded SRTM 1 sec successfully using gpt, but now it has ‘WARNING: org.esa.snap.dem.dataio.srtm1_hgt.SRTMHGTReader: Unable to read SRTM HGT: invalid block type’. and process seems never to stop.

#7

Hello everyone.

I am working on a project of ground subsidence for an areas in Vietnam. I have created a graph where i automated the InSAR process. The issue comes in the TopoPhaseRemoval step where i get the following warning:

WARNING: org.esa.snap.dem.dataio.srtm1_hgt.SRTMHGTReader: Unable to read SRTM HGT: invalid code lengths set

In the TopoPhaseRemoval parameters, I have set SRTM 1Sec HGT as the demName.
I do get the DEM in the end, it looks fine, but i do not know whether i should worry about this warning message or not. Never seen this before

If anyone has any clue about this warning, it would be helpful to know whether it’s something to ignore or not