Question about ground control scene attribute, what is "uncertain"



  • Frank Warmerdam


    We are not currently able to give a great metric for positional accuracy.  If ground_control is True we believe we are within our positional accuracy specification, while when it is False we are not at all confident.  It will be set to False in a number of cases:

     - we only have original satellite pointing information (often hundreds of meters off)

     - we only have positioning based on correcting the satellite pointing based on nearby scenes tie down. 

     - we only have control points tieing this scene to neighbours, but none directly to the ground reference. 

     - or lastly we only have a few tiedown points and our trust level in the result is low.

    If things being off by more than 10m is a problem, you should exclude anything with ground_control set to False.  We are contemplating offering more granularity of positional accuracy in the future, but we are still reviewing what would be possible and helpful.


    Best regards,


    Comment actions Permalink
  • Ryan Avery

    Thanks Frank! we noticed a few outlier scenes over Ghana that were about 10 pixels or >30 meters off, we will try the boolean filter. 

    Comment actions Permalink

Please sign in to leave a comment.