Snaphu import after using BatchSnaphuUnwrapOp

Hello

I have been working on a processing workflow to perform SBAS with SNAP and export to PyRate. My SNAP version is 11

The screenshot below shows the images I am working with:
image

My current processing steps are broken up into multiple XML graphs that perform the following steps and are executed via gpt calls on the command line:

for file in files:
Graph 1: Apply orbit file → TOPSAR-Split
done

Graph 2: ProductSet-ReaderBack-geocoding
Graph 3: Add Elevation → MultiMasterInSARTOPSAR-DeburstSubsetGoldsteinPhaseFiltering
Graph 4: Snaphu Export
Graph 5: BatchSnaphuUnwrapOp

Up to this point everything functions correctly and I have produced the desired unwrapped phase data as shown in the screenshot
image

The next steps I need to apply are Snaphu Import and Terrain Correction before exporting to PyRate.

Since I have performed a batch unwrap, I have a single unwrapped stack with the unwrapped phase files in it. It doesn’t look like the SnaphuImport operator can deal with a data stack.

My question is: Is there a way that I can import this data back into SNAP in one step and perform terrain correction on this stack. Or do I need to operate on individual files from now on and loop through the files.

Update: I am now questioning whether I need the SnaphuImport step since the result of the Batch operation can be read directly. When I try to perform the terrain correction directly on the unwrapped stack I receive the following error:

Error: java.lang.NullPointerException
org.esa.snap.core.gpf.OperatorException: java.lang.NullPointerException
        at org.esa.snap.core.gpf.graph.GraphProcessor$GPFImagingListener.errorOccurred(GraphProcessor.java:389)
        at com.sun.media.jai.util.SunTileScheduler.sendExceptionToListener(Unknown Source)
        at com.sun.media.jai.util.SunTileScheduler.scheduleTile(Unknown Source)
        at javax.media.jai.OpImage.getTile(Unknown Source)
        at javax.media.jai.PlanarImage.getData(Unknown Source)
        at com.bc.ceres.glevel.MultiLevelImage.getData(MultiLevelImage.java:64)
        at org.esa.snap.core.gpf.internal.OperatorContext.getSourceTile(OperatorContext.java:449)
        at org.esa.snap.core.gpf.internal.OperatorContext.getSourceTile(OperatorContext.java:435)
        at org.esa.snap.core.gpf.internal.OperatorImageTileStack.computeRect(OperatorImageTileStack.java:116)
        at org.esa.snap.core.gpf.internal.OperatorImageTileStack.computeTile(OperatorImageTileStack.java:86)
        at com.sun.media.jai.util.SunTileScheduler.scheduleTile(Unknown Source)
        at javax.media.jai.OpImage.getTile(Unknown Source)
        at com.sun.media.jai.util.RequestJob.compute(Unknown Source)
        at com.sun.media.jai.util.WorkerThread.run(Unknown Source)
Caused by: org.esa.snap.core.gpf.OperatorException: java.lang.NullPointerException
        at org.esa.snap.engine_utilities.gpf.OperatorUtils.catchOperatorException(OperatorUtils.java:434)
        at eu.esa.sar.sar.gpf.geometric.RangeDopplerGeocodingOp.computeTileStack(RangeDopplerGeocodingOp.java:1104)
        at org.esa.snap.core.gpf.internal.OperatorImageTileStack.computeRect(OperatorImageTileStack.java:122)
        at org.esa.snap.core.gpf.internal.OperatorImageTileStack.computeTile(OperatorImageTileStack.java:86)
        ... 12 more
Caused by: java.lang.NullPointerException
        at eu.esa.sar.sar.gpf.geometric.RangeDopplerGeocodingOp.computeTileStack(RangeDopplerGeocodingOp.java:955)
        ... 14 more

This error occurs regardless of the DEM selected to perform the terrain correction.

Thanks