SNAP 12: MultiMasterInSAR fails on TerraSAR-X SSC stack with “Undefined symbol i_ifg_” (works in SNAP 9)

snap Problem Reports
1

Hello STEP team,

I am having the following issue with SNAP 12: the MultiMasterInSAR operator fails at ~90% with “Undefined symbol i_ifg_” on a TerraSAR-X SSC stack. The exact same graph + data complete successfully in SNAP 9.

Environment

  • SNAP: 12…0.0
  • Also tested: SNAP 9.0.0 (same data/graph completes successfully)
  • OS: Ubuntu

Data

  • Sensor/Mode: TerraSAR-X (TDX1) SSC, SM S_SRA
  • Input product: a prebuilt stack DIMAP generated with SNAP 12.0.0

Reproduction steps

  1. Use the attached graph (mmifg.xml) that reads the TerraSAR-X stack and applies MultiMasterInSAR, then Write.
  2. Run:
    1. run through GUI (same issue through gpt)
  3. Processing advances to 90% and then fails during WriteOp.

Observed

Console excerpt (full logs attached as stdlog.txt / errlog.txt):

Executing processing graph
90% done.
java.lang.IllegalArgumentException: expression: Undefined symbol 'i_ifg_'.
    at org.esa.snap.core.image.VirtualBandOpImage.parseExpression(VirtualBandOpImage.java:108)
...
Caused by: org.esa.snap.core.jexp.ParseException: Undefined symbol 'i_ifg_'.
    at org.esa.snap.core.jexp.impl.ParserImpl.reportError(ParserImpl.java:1036)
...
Error: expression: Undefined symbol 'i_ifg_'.

No output generated

Expected

  • MultiMasterInSAR should complete and write the output product (as it does with the same inputs/graph in SNAP 9).

stdlog.txt (37 Bytes)
errlog.txt (8.6 KB)
mmifg.xml (1.6 KB)

2

This is the same error I encountered with snap 12 and a stack of SLC bursts which I reported in another thread on this forum yesterday.
So I tried my workflow with snap 9 and it works as well…
Looks as if MultiMasterInSAR has a bug then.

3

@jun_lu can you have a look?
Thank you

4

@lveci can you have a look?
Thank you

5

How do you create the stack given as input to the MultiMasterInSAR operator? Can you share this information as well?
Had you then manage to get it working with SNAP 9 even for Sentinel-1 SLC bursts?

6

Hi,
I downloaded the bursts using burst2safe before applying the following chain:
ApplyOrbit->BackGeocoding->ESD->Deburst->Elevation->Subset->MultiMasterInSAR
That got processed without issues using Snap 9 but failed in Snap 12.