Idepix OLCI with subset

Optical Toolbox
1

I am trying to process S3A Level 1 images on SNAP 11. The process involves subset and then Idepix.olci, previously this has worked fine on SNAP V9. I have just updated SNAP to the current version and when I run my code, I receive this error:

Error: [NodeId: Idepix.Olci] Product 'Slope-Aspect-Orientation' does not contain a raster with name 'OZA_interp'

or

Error: [NodeId: Idepix.Olci] Selected cloud screening algorithm cannot be used with given input product. Supported sensors are: MERIS, SPOT VGT, MODIS, Landsat-8, SeaWiFS, Sentinel-2 MSI, Sentinel-3 OLCI, PROBA-V, VIIRS. org.esa.snap.core.gpf.graph.GraphException: [NodeId: Idepix.Olci] Selected cloud screening algorithm cannot be used with given input product.

The same issue occurs when I try and run this on using the GUI even when i subset all of the tie-point grids.

The OZA files are in the Tie-Point Grids folder both for the full scene and after I subset the scene (without Idepix).

When I run Idepix.Olci on the full image first then subset it works fine so I think the subset process is not retaining the ‘OZA_interp’. Does anyone know how I can subset the image first and then Idepix without losing the OZA_interp raster?

Example image: S3A_OL_1_EFR____20190714T104001_20190714T104301_20190715T145430_0179_047_051_1980_LN1_O_NT_002.SEN3

Graph subset > idepix (Not working):

temp_20190714_Region3986_not_working.xml (2.2 KB)

Graph idepix > subset (working)

temp_20190714_Region3986_working.xml (2.2 KB)

2

@dolaf could you have a look?
Thank you

3

Hi,

the reason for this problem is that the signature for the product type for subsets has slightly changed from SNAP 9 to 10/11, and this has not been properly adapted in Idepix OLCI.

We will fix this and provide the fix in a module update for SNAP 11 or, latest, with the next version SNAP 12.

For the moment, in case you are not doing ‘mass processing’ and just have a reasonable number of input subsets to process, you could change the product type manually in SNAP Desktop to get it running:

  • select the subset product in Product Explorer
  • right-click, then right-click ‘Properties’
  • In the Product Node Properties window, edit the field ‘Product Type’ with the three dots on the right
  • if you change ‘Derived from (OL_1_EFR)’ to ‘Derived from OL_1_EFR’ (just remove the brackets), Idepix should work

product_type_workaround
product_type_workaround903×721 96.1 KB

In general, please note that for any preprocessing or L2 processor the functionality may be limited or the processing might fail if you use just subsets of the originally supported input products. Subsets may look very different (spatial or band subsets, metadata included or not, etc.), thus essential information might be missing.

Cheers,
Olaf

4

Hi Olaf,

This update would be really appreciated. This is preventing us from upgrading SNAP v9 in our automated pipelines.

Thanks for your work!

Cheers

James