Schedule for SPOT4 (Take5) reprocessing

We should be able to start reprocessing  SPOT4(Take5) data in January, and to release them in February (it is always risky to announce a date, we have already announced November, then December). This new version will also be produced on MUSCATE prototype processing center, implemented at CNES, for the THEIA Land data center.

 

Why does it take so long ?

 

  • The longest part was the negociation between CNES and CAP GEMINI about the modifications of MUSCATE.
  • The modification itself took a while, as it includes :
    • A major version change of SIGMA, which is CNES software for ortho-rectification. This new version will allow us to improve geometric accuracy using new reference images to take ground control points (GCPs), while the previous version only allowed us to work with LANDSAT 5 or 7, while the other solutions did not work because of a strange bug. Instead of LANDSAT 5 and 7, we will use the GEOSUD mosaic over France, which is a high quality mosaic produced by IGN, that covers the whole France. Elsewhere, we will use LANDSAT 8, which also provides a large gain in accuracy. And for the 4 sites, whose ortho-rectification was most difficult, we will the most cloudfree SPOT4(Take5) image as référence, which should provide us better quality GCPs.
    • We will be able to tell normal Level 1C failures due to cloud cover from possibly abnormal ones.
    • We will at last be able to process NASA's maricopa site, y separating it in two sites, one taken from the East, and the other from the West.
    • The level 2A chain was updated, and we will use a new aerosol model, with slightly larger particle sizes, which provide better results.
    • The Level 2 will provide 2 new flags that indicate the pixels for which the slope correction cannot be performed, for instance because these pixels lie in the shadow. We had forgotten these flags in our first version.
    • I do not know whether you are using the saturation masks or not. But these ones had a few defects that will be corrected in this new version.
    • The level 2A products will also contain nice quicklooks, on which clouds and shadow will be circled in colors. We will use them to perform a quicker validation of the processing, and we hope they will be useful for you too.
  • Until the end of the year, we will install the new version of MUSCATE prototype, then the processors, the parameters, and the new image references. The preparation of 45 reference images is quite some work.
  • Then, banzaï !,  we will validate all this stuff and start the reprocessing of version 2.0 of  SPOT4 (Take5) data.

 

 

Posted under: Corrections (geometry, atmosphere, clouds), In English, SPOT4 (Take 5), THEIA

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