Error converting phase to elevation for DEM generation

ABraun · May 18, 2017, 6:55am

yes, Sentinel-1 is no competition to the quality that can be achieved with TanDEM-X data. Looks great.

To get rid of the square-ish artefacts, you can change the number of tiles in the unwrapping config-file and compare. I assume that they are related to these tiles somehow.

ABerni · May 18, 2017, 6:59am

Thats a very good idea! Thank you, I will try definitely changing the tiles today!

Anton_Gorshkov · June 2, 2017, 12:16pm

Hello, I can not find " src/snaphu_io.c file" Where it can be found?

ABraun · June 2, 2017, 2:02pm

it is located in \snaphu-v1.4.2\src and usually found by the make command.

Anton_Gorshkov · June 5, 2017, 7:12am

Thanks, I downloaded mint 64 and VMmare player, but there is no file “src / snaphu_io.c file”. When you download separately the archive snaphu-v1.4.2, there is “snaphu_io.c”. But how do I unwrapping the phase? Need to install snaphu-v1.4.2?

ABraun · June 5, 2017, 8:42am

I have no experience with vmware, but here is a tutorial I made for snaphu under windows

Anton_Gorshkov · June 5, 2017, 9:53am

Thanks, I’ll try to do a unwrapping the phase with cygwin

Anton_Gorshkov · June 7, 2017, 5:49am

Hello, ABraun! The file that creates cygwin “SNAPHU.EXE”, is it universal for unwrapping the phase for all radar space image?

ABraun · June 7, 2017, 5:53am

yes, worked on all sensors for me so far. Please read here:
https://web.stanford.edu/group/radar/softwareandlinks/sw/snaphu/snaphu_man1.txt

Anton_Gorshkov · June 8, 2017, 5:31am

After the unwrapping phase scan for Sentinel-1, we obtain the values of the displacements of the earth’s surface, they are measured in centimeters or meters?

gabrielaquintana77 · June 8, 2017, 12:19pm

Hi Anton_Gorshkov

In my experience, the values are for default in meters, but you can to convert to cm or mm!

smohit · June 12, 2017, 6:12am

Hi Everyone,

i am facing some problem (Java.lang.NullPointerException) while generating DEM through Interferometric->Products->Phase to Elevation even using SNAP 5.0. (latest updated) on OS windows 8.
If i go for Interferometric->Products->Phase to Height, nothing is happening.
@squeakus did you get the solution for this problem?
Error is:
org.esa.snap.core.gpf.OperatorException: java.lang.NullPointerException
at org.esa.snap.engine_utilities.gpf.OperatorUtils.catchOperatorException(OperatorUtils.java:421)
at org.esa.s1tbx.insar.gpf.PhaseToElevationOp.computeTileStack(PhaseToElevationOp.java:336)
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)
Caused: org.esa.snap.core.gpf.OperatorException: java.lang.NullPointerException
at org.esa.snap.core.gpf.internal.OperatorExecutor$GPFImagingListener.errorOccurred(OperatorExecutor.java:376)
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)
[catch] at com.sun.media.jai.util.WorkerThread.run(SunTileScheduler.java:468)

muhammadnurulfahmi · June 12, 2017, 8:46am

I have same error java.lang.nullPointerException while generating DEM from phase. Could anyone solved this error?

susantojoy · August 7, 2017, 12:04pm

I use single subswath of Sentinel 1 SLC of Indian subcontinent I also java.lang.nullPointerException when I use phase to elevation or phase to height. How can I solve the problem.

swatishree · September 13, 2017, 6:12am

sir,
I tried phase unwrapping in ubuntu 14.04 LTS . When i run the command -
snaphu -f snaphu.conf Phase_ifg_HH_23Dec2009_26Dec2010.snaphu.img 4672,
it gives an error saying-
snaphu v1.4.2 27 parameters input from file snaphu.conf (84 lines total) only one tile–disregarding multiprocessor option Logging run-time parameters to file snaphu.log
Segmentation fault (core dumped)
Please guide me through this. I am not using cygwin terminal.
Thanks

PauloCesar · October 24, 2017, 1:44pm

hey Anna! this results it´s the same region ?

PauloCesar · October 24, 2017, 5:12pm

hey @squeakus, the same thing happended to me when i used snap… try to use s1 toolbox interface, because it worked for me transform Phase to Height.

ABerni · October 25, 2017, 6:51am

Hey Paulo,
yes, the first one is the original srtm and the pic below is the result of the dem generation (obviously wrong) for the same subset.

Mounika · January 2, 2018, 12:26pm

Hello everybody,

I am also facing the same problem while trying phase to elevation. getting the following error.

org.esa.snap.core.gpf.OperatorException: java.lang.NullPointerException
at org.esa.snap.engine_utilities.gpf.OperatorUtils.catchOperatorException(OperatorUtils.java:421)
at org.esa.s1tbx.insar.gpf.PhaseToElevationOp.computeTileStack(PhaseToElevationOp.java:336)
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)
Caused: org.esa.snap.core.gpf.OperatorException: java.lang.NullPointerException
at org.esa.snap.core.gpf.internal.OperatorExecutor$GPFImagingListener.errorOccurred(OperatorExecutor.java:376)
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)
[catch] at com.sun.media.jai.util.WorkerThread.run(SunTileScheduler.java:468)

please try to help…thank you in advance…

Mounika · January 5, 2018, 6:12am

hello @PauloCesar,

how can i select only s1 toolbox? it is not found if search it…only snap is available… kindly, please help me out …

Thanks in advance…