S3 preprocessing xml source bands does not match downloaded product

snap Sen-ET
1

i am working on the sen-et plugin, but im trying to run it manually through python.

after downloading the sentinel 3 product the next step is the preprocessing.

the source bands in the provided sentinel3 preprocessing xml are not found in the s3 product. the bands in question are (sat_zenith_tn,solar_zenith_tn,latitude_tx,longitude_tx) is there something i am missing ?

the error I’m getting:

rror: [NodeId: Subset] Operator ‘SubsetOp’: Value for ‘Source Bands’ is invalid: ‘solar_zenith_tn’

2

well this was solved by loading the xml graph to snap desktop, loading an example product, then saving the graph and using it.

3

I had exactly the same problem… But this is still a problem if you want to call this functionality from python or integrate in some processing chain. Anybody of the SNAP developers that can help us with this?

4

Can you maybe post the graph xml file?
The names mentioned above are the tie-point grids of SLSTR data.
Maybe the provided xml is not correct.
So they actually should be specified in the tag tiePointGridNames of the subset node:

<graph id="someGraphId">
  <version>1.0</version>
  <node id="someNodeId">
    <operator>Subset</operator>
    <sources>
      <source>${source}</source>
    </sources>
    <parameters>
      <sourceBands>string,string,string,...</sourceBands>
      <region>rectangle</region>
      <referenceBand>string</referenceBand>
      <geoRegion>geometry</geoRegion>
      <subSamplingX>int</subSamplingX>
      <subSamplingY>int</subSamplingY>
      <fullSwath>boolean</fullSwath>
      <tiePointGridNames>string,string,string,...</tiePointGridNames> 
      <copyMetadata>boolean</copyMetadata>
    </parameters>
  </node>
</graph>
5

Hi Marco, thanks for your reply. I actually just took the XML that comes as an example with the plugin. Just changed the paths to my inputs and I get the error when using gpt on the command line. Works ok when used from the GUI.

I attach the graph XML here.sentinel_3_pre_processing.xml (6.3 KB)

6

loading the xml to snap shows what options you can choose and apparently solar_zenith_tn was not one of these options hence the error.

7

I ran it as it is from the GUI and worked fine… it’s the command line the problem.

8

the graph worked from the command line,

but now I’m stuck at the data mining sharpener where the output is always blank, so i don’t know if messed up somewhere.

9

Hi,

Anyone found a solution on this issue ? It indeed works fine through SNAP but not with gpt command line… The output_geometry_observation file is empty.
I use the exact same xml provided by the plugin…