Problem with gpt Terrain-Flattening

s1tbx
#1

When running a Terrain-Flattening process with gpt I got the following error :

/opt/snap/bin/gpt Terrain-Flattening -t /home/S1A_IW_GRDH_1SDV_20150513T100637_20150513T100702_005901_0079A1_E274/S1A_IW_GRDH_1SDV_20150513T100637_20150513T100702_005901_0079A1_E274_OB_CAL_TF -Ssource=/home/S1A_IW_GRDH_1SDV_20150513T100637_20150513T100702_005901_0079A1_E274/S1A_IW_GRDH_1SDV_20150513T100637_20150513T100702_005901_0079A1_E274_OB_CAL.dim -PdemName="SRTM 3Sec" 

The DEM resolution is lower than that of the source image. Please multilook the source image or use higher resolution DEM (e.g. SRTM 1Sec HGT) to make sure the DEM resolution is higher than that of the source image.
org.esa.snap.core.gpf.OperatorException: The DEM resolution is lower than that of the source image. Please multilook the source image or use higher resolution DEM (e.g. SRTM 1Sec HGT) to make sure the DEM resolution is higher than that of the source image.
	at org.esa.snap.engine_utilities.gpf.OperatorUtils.catchOperatorException(OperatorUtils.java:421)
	at org.esa.s1tbx.sar.gpf.geometric.TerrainFlatteningOp.initialize(TerrainFlatteningOp.java:190)
	at org.esa.snap.core.gpf.internal.OperatorContext.initializeOperator(OperatorContext.java:486)
	at org.esa.snap.core.gpf.internal.OperatorContext.getTargetProduct(OperatorContext.java:273)
	at org.esa.snap.core.gpf.Operator.getTargetProduct(Operator.java:387)
	at org.esa.snap.core.gpf.main.CommandLineTool.runOperator(CommandLineTool.java:306)
	at org.esa.snap.core.gpf.main.CommandLineTool.runGraphOrOperator(CommandLineTool.java:284)
	at org.esa.snap.core.gpf.main.CommandLineTool.run(CommandLineTool.java:188)
	at org.esa.snap.core.gpf.main.CommandLineTool.run(CommandLineTool.java:121)
	at org.esa.snap.core.gpf.main.GPT.run(GPT.java:54)
	at org.esa.snap.core.gpf.main.GPT.main(GPT.java:34)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.esa.snap.runtime.Launcher.lambda$run$0(Launcher.java:55)
	at org.esa.snap.runtime.Engine.runClientCode(Engine.java:189)
	at org.esa.snap.runtime.Launcher.run(Launcher.java:51)
	at org.esa.snap.runtime.Launcher.main(Launcher.java:31)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at com.exe4j.runtime.LauncherEngine.launch(LauncherEngine.java:65)
	at com.install4j.runtime.launcher.UnixLauncher.main(UnixLauncher.java:57)

That is really strange because it happens with SRTM 3Sec and SRTM 1Sec HGT. So I do know what is downloaded by Snap at the end. Am I forced to download the correct DEM file by myself ?

#2

Currently the DEM is not upsampled. You need to bring the SAR image down to the resolution of the DEM via multilooking.

#3

Thank you very much for your answer.

The SNAP environment is quite new for me. Could you tell me the approach to retrieve the DEM resolution and input it to the multilook operator ?

Regards,