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  1. Data Management
  2. DM-1970

Make DistortedTanWcs persistable

    Details

    • Type: Improvement
    • Status: Won't Fix
    • Resolution: Done
    • Fix Version/s: None
    • Component/s: afw
    • Labels:
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    • Team:
      Data Release Production

      Description

      The new DistortedTanWcs class (DM-1969) is not persistable. It would be nice if it was.

      One complicating factor is that DistortedTanWcs contains an arbitrary XYTransform, and that class hierarchy is not yet persistable.

      One option is to persist it as a TAN-SIP WCS. This would probably be good enough (especially since DistortedTanWcs is only intended as an approximation before astrometry is fit) and it would be fairly easy to do. However, the lack of true round-trip would probably cause unwelcome surprises.

      Even if true round-trip ability is implemented, it would probably be wise to also write a TAN-SIP approximation to the FITS files, so that utilities such as ds9 can take advantage of it. Presumably additional metadata could tell the LSST code to unpersist the WCS as a DistortedTanWcs instead of a TAN-SIP WCS (TanWcs).

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              • Assignee:
                rhl Robert Lupton
                Reporter:
                rowen Russell Owen
                Watchers:
                Russell Owen
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                  Updated:
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