Hello,
I made SNAP (v7) graph to correct Sentinel-1 images from Finland, consisting of steps: Calibration, Terrain-Flattening, Terrain-Correction and LinearToFromdB. I got error message “Unable to download http://step.esa.int/auxdata/dem/egm96/ to null”. I am using External DEM. SNAP v6 did not have this problem.
What’s wrong?
Best regards, Markus Törmä
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Same here. Logs are:
INFO: org.esa.snap.engine_utilities.download.DownloadableContentImpl: http retrieving http://step.esa.int/auxdata/dem/egm96/ww15mgh_b.zip
org.esa.snap.core.gpf.OperatorException: Unable to download http://step.esa.int/auxdata/dem/egm96/ to null
at org.esa.snap.core.gpf.graph.GraphProcessor$GPFImagingListener.errorOccurred(GraphProcessor.java:363)
at com.sun.media.jai.util.SunTileScheduler.sendExceptionToListener(SunTileScheduler.java:1646)
at com.sun.media.jai.util.SunTileScheduler.scheduleTile(SunTileScheduler.java:921)
at javax.media.jai.OpImage.getTile(OpImage.java:1129)
at javax.media.jai.PlanarImage.getData(PlanarImage.java:2085)
at com.bc.ceres.glevel.MultiLevelImage.getData(MultiLevelImage.java:64)
at org.esa.snap.core.gpf.internal.OperatorContext.getSourceTile(OperatorContext.java:407)
at org.esa.snap.core.gpf.internal.OperatorContext.getSourceTile(OperatorContext.java:393)
at org.esa.snap.core.gpf.internal.OperatorImage.computeRect(OperatorImage.java:73)
at javax.media.jai.SourcelessOpImage.computeTile(SourcelessOpImage.java:137)
at com.sun.media.jai.util.SunTileScheduler.scheduleTile(SunTileScheduler.java:904)
at javax.media.jai.OpImage.getTile(OpImage.java:1129)
at com.sun.media.jai.util.RequestJob.compute(SunTileScheduler.java:247)
at com.sun.media.jai.util.WorkerThread.run(SunTileScheduler.java:468)
Caused by: org.esa.snap.core.gpf.OperatorException: Unable to download http://step.esa.int/auxdata/dem/egm96/ to null
at org.esa.snap.engine_utilities.gpf.OperatorUtils.catchOperatorException(OperatorUtils.java:415)
at org.esa.s1tbx.sar.gpf.geometric.RangeDopplerGeocodingOp.computeTileStack(RangeDopplerGeocodingOp.java:1063)
at org.esa.snap.core.gpf.internal.OperatorImageTileStack.computeRect(OperatorImageTileStack.java:116)
at org.esa.snap.core.gpf.internal.OperatorImageTileStack.computeTile(OperatorImageTileStack.java:85)
at com.sun.media.jai.util.SunTileScheduler.scheduleTile(SunTileScheduler.java:904)
... 11 more
Caused by: java.io.IOException: Unable to download http://step.esa.int/auxdata/dem/egm96/ to null
at org.esa.snap.dem.dataio.EarthGravitationalModel96.<init>(EarthGravitationalModel96.java:100)
at org.esa.snap.dem.dataio.EarthGravitationalModel96.create(EarthGravitationalModel96.java:85)
at org.esa.snap.dem.dataio.EarthGravitationalModel96.instance(EarthGravitationalModel96.java:77)
at org.esa.snap.dem.dataio.DEMFactory.getLocalDEM(DEMFactory.java:185)
at org.esa.s1tbx.sar.gpf.geometric.RangeDopplerGeocodingOp.computeTileStack(RangeDopplerGeocodingOp.java:864)
... 14 more
Error: Unable to download http://step.esa.int/auxdata/dem/egm96/ to null
NB the logs might be a bit garbled because of multiple parallel jobs.
Seems to be intermittent - when I ran the same task again, it did not fail. Probably another hickup with SNAP’s aux data downloads.
based on your logfile the EGM96 cannot be downloaded. Have you tried removing this option?
I put the ’ ww15mgh_b.zip’ in the file ‘C:\Users*.snap\auxdata\dem\egm96 ’ , and put the DEM from SRTM website in 'C:\Users*.snap\auxdata\dem\SRTM 3Sec’. The problem is solved.
1 Like
thank you for sharing a solution
Hi
I can’t download Strm,
Can you explain how you did What values are the option of the Elevation Plot and the dem DEM when you are using the strm ?
Hello hiny thank you for the solution ,you actually downloaded the correction file for egm96 and pasted it right.I am currently in the same step.I downloaded DEM file from CGIAR CSI just like you and doing the Coregistration in SNAP offline mode.But the issues with me is my area of interest is covering 2 of the 55 grids ,so do i have to paste the 2 zip files to .snap\auxdata\dem\egm96\ or do i have to select the whole 3030 grid.