Back-Geocoding fails with “Entire image is outside of SRTM valid area” when using Copernicus 30 m DEM in esa_snappy

Microwave Toolbox
1

I’m trying to run Back-Geocoding in Python using snappy (SNAP 12.0) with the Copernicus 30 m Global DEM, but I keep getting this error:

RuntimeError: org.esa.snap.core.gpf.OperatorException:
Entire image is outside of SRTM valid area.
Please use another DEM.

However, the AOI is in northern Norway (around Alta, 69° N) — well within Copernicus DEM coverage.

Here’s the relevant Python snippet:

from esa_snappy import GPF, HashMap

coreg_params = HashMap()
coreg_params.put(“DEMName”, “Copernicus 30m Global DEM”)
coreg_params.put(“DEMResamplingMethod”, “BILINEAR_INTERPOLATION”)
coreg_params.put(“ResamplingType”, “BILINEAR_INTERPOLATION”)
coreg_params.put(“MaskOutAreaWithoutElevation”, True)
coreg_params.put(“OutputDerampAndDemodPhase”, False)
coreg_params.put(“DisableReramp”, False)

coreg = GPF.createProduct(“Back-Geocoding”, coreg_params, [orbit_2, orbit_1])

SNAP desktop work as expected.

Thanks in advance!
Pritimoy Podder

2

@dolaf, could you please have a look?

3

Hi,

I doubt that this issue is related to the use of Python or esa_snappy.

To reproduce and investigate the problem, could you please provide a bit more information:

  • your full Python script to better understand, e.g., what is orbit_2, orbit_1?
  • the input product(s) you are using
  • What is the corresponding workflow in SNAP desktop which you say ‘works as expected’?

Many thanks,
Olaf

1 Like
4

Hello,
I have the same issue with a few Sentinel 2 images (for example: S2A_MSIL1C_20170622T104021_N0500_R00T32WPS_20231012T033537.SAFE)
this is the python script invoking snappy.

(coordinates used for polygon were: minlon : 12.212123, maxlon 12.317597 , minlat : 64.773622, maxlat: 64.818538)

product = ProductIO.readProduct(input_file)

params = HashMap()
params.put(“targetResolution”, JInt(res))
params.put(“upsampling”, “Nearest”)
params.put(“downsampling”, “Mean”)
params.put(“flagDownsampling”, “First”)
params.put(“resampleOnPyramidLevels”, False)

resampled = GPF.createProduct(“Resample”, params, product)

params_subset = HashMap()

params_subset.put(“geoRegion”,
"POLYGON((%f %f, %f %f, %f %f, %f %f, %f (minlon, maxlat, maxlon, maxlat, maxlon, minlat, minlon, minlat, minlon, maxlat))

subset = GPF.createProduct(“Subset”, params_subset, resampled)

params_ide = HashMap()
params_ide.put(‘copyToaReflectances’,False)
params_ide.put(‘computeMountainShadow’,True)
params_ide.put(‘computeCloudShadow’,False)
ide = GPF.createProduct(‘Idepix.S2’,params_ide,subset)

ProductIO.writeProduct(ide, output_nc,“NetCDF4-BEAM”)