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  1. Data Management
  2. DM-5425

Provide an easy way to set Coord fields of a source catalog


    • Type: Improvement
    • Status: To Do
    • Resolution: Unresolved
    • Fix Version/s: None
    • Component/s: afw
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    • Team:
      Alert Production


      We sometimes need to set the coord fields of a source catalog, e.g. when fitting a new WCS or when studying an `icSrc` catalog (whose Coord field is not set). It would be nice to have a central, easily found way to do this. Right now we have the following as a static method of `TanSipWcsTask`, which works fine but is in a poor location:

          def updateSourceCoords(wcs, sourceList):
              """Update coords in a collection of sources, given a WCS
              if len(sourceList) < 1:
              schema = sourceList[1].schema
              srcCoordKey = afwTable.CoordKey(schema["coord"])
              for src in sourceList:
                  src.set(srcCoordKey, wcs.pixelToSky(src.getCentroid()))

      The other direction is also useful for reference catalogs, though from a practical standpoint the only user is probably `meas_astrom`. Even so, I suggest that this be made publicly available in the same way. Again, this is presently a static method of `FitTanSipWcsTask`:

          def updateRefCentroids(wcs, refList):
              """Update centroids in a collection of reference objects, given a WCS
              if len(refList) < 1:
              schema = refList[0].schema
              coordKey = afwTable.CoordKey(schema["coord"])
              centroidKey = afwTable.Point2DKey(schema["centroid"])
              for refObj in refList:
                  refObj.set(centroidKey, wcs.skyToPixel(refObj.get(coordKey)))

      I hope this can remain Python code, but admit that the extra speed of C++ might come in handy in some cases. In any case, once the function is in a central location we can implement it in C++ if we find the need.


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              • Assignee:
                rowen Russell Owen
                Jim Bosch, John Parejko, John Swinbank, Russell Owen
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                • Created:

                  Summary Panel