Band Select Op in the GraphBuilder not working properly in SNAP 13?

snap Problem Reports
1

As the title suggests, it appears that the Band Select operator in SNAP 13 is not working properly within the GraphBuilder. It does not appear in the processing steps tabs, and any graph that contains the Band Select operator cannot be used.

The red error message reads:

Error: [NodeID: BandSelect] Cannot read the array length because local5 is null.

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2

Jira ticket SNAP-4092 created

1 Like
3

I have a similar isue
When performing co-registration of two Sentinel-1 IW SLC products in SNAP 13, the software changes the selected sub-swath (IW3) to IW1 during processing, even though IW3 is explicitly chosen by the user in the S-1 TOPS Coregistration parameters.
This behavior prevents the user from processing the desired subswath and disrupts automated workflows.

Steps to Reproduce:

  1. Open the following Sentinel-1 SLC products in SNAP (any recent version):

    • S1A_IW_SLC__1SDV_20200731T033531_20200731T033558_033693_03E7B2_D1A9.zip

    • S1B_IW_SLC__1SDV_20200806T033445_20200806T033512_022797_02B43D_3A0B.zip

    • or

    • S1B_IW_SLC__1SDV_20200806T033445_20200806T033512_022797_02B43D_3A0B.zip

    • S1B_IW_SLC__1SDV_20200725T033445_20200725T033512_022622_02AEEE_A0BA.SAFE.zip

  2. Apply orbit files to both products.

  3. Run S-1 TOPS Coregistration.

  4. In the S-1 Back Geocoding operator, manually select IW3 as the processing subswath.

Observed Behavior:

  • SNAP silently overrides the selected sub-swath (IW3) and replaces it with IW1 in the processing chain. The final output only contains IW1, regardless of user selection.

Users with snap 10 or 12 does not have these isue.

4

The issue has been fixed. The correction will be included in the next SNAP minor update.

1 Like
5

Hello !

The band select operator now works perfectly fine, but I still have the issue with the TOPS SPLIT operator that automatically overrides IW1, do you know if it will be fixed soon ?

Thanks for reading