FAQ

Can we access the panchromatic data of SPOT (Take5) experiments ?

Sorry, no, as the experiment is dedicated to prepare for Sentinel-2, which does not have a Panchromatic band, it was decided not to produce the panchromatic bands to reduce the cost.

 

Why are some dates missing in the Level 1C Take5 time series, and some more in the level 2A time series ?

In some few cases, SPOT5 (Take5) data were lost, either in two periods for which all the data were lost,  or because some L1A products were not editable because the segment length was too short (this happened mainly at the beginning of experiment) but in most cases, the absence of data is related to the cloud cover. The list of images which were not processed to level 1A because of technical reasons not related to cloud cover is provided here.

If the missing date you search is not on that list, it is then probably missing because the product was to cloudy to be processed at Level 1C or Level 2A. At Level 1C, as ground control points are necessary to ensure the registration performance, the images cannot be processed if the amounts of clear pixels is not sufficient. At Level 2A, an image is discarded if the cloud mask contains more than 90% of pixels.

 

How to download all the dates from a SPOT (Take5) site  ?

Easy, it is explained here .

 

What is the SPOT(Take5) product format ?

The SPOT (Take5) product format is explained here.

 

What is in the PRIVE directory within the LEVEL 2A product  ?

As you probably know, our LEVEL 2A methods are recurrent. The PRIVE ("private") directory provides all the information needed to process date D+1 from the Level 2A product obtained at date D. All this information is available at 200 m resolution. It is therefore internal data and we think that you do not need to have look at it. It is useful for us for quality control.

 

Where are the sun and viewing angles in SPOT (Take5) products ?

In the XML header file. The angles are described here. They are provided for the center of the scene. The SPOT(Take5) swath is 4 degrees for sites observed by only one instrument (60km), and 8 degrees for bi-instrument scenes (120 km). Maximum viewing angle approximation error is therefore 2 degrees for mono-instrument and 4 degrees for bi-instrument images, at the edge of the Swath.

2 comments

  • Olivier Tsui on 24/02/2014 at 22:36 said:

    Hello,

    I am trying to download from the the SPOT4 (Take5) download server. However when the downloaded file reaches about 20MB the connection disconnects each time. I have tried multiple internet browsers and images. All with the same result.

    Is there an alternate way to downloaded these scenes.?

    Thank you.

    • Olivier Hagolle on 26/02/2014 at 12:53 said:

      In order to help us investigate, could you please tell us if your problem is due to a particular product/data or to any of them ?
      For your information, we are currently reprocessing the whole SPOT4-Take5 data set. If everything goes well, the new version will be available in less than 2 weeks.
      Olivier

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