lsst.meas.astrom.setMatchDistance Namespace Reference

Functions
	setMatchDistance (matches)

Function Documentation

setMatchDistance()

lsst.meas.astrom.setMatchDistance.setMatchDistance

(

matches

)

Set the distance field of the matches in a match list to the distance in
radians on the sky.

Parameters
----------
matches : `list` of `lsst.afw.table.ReferenceMatch`
    a list of matches, reads the coord field of the source and reference
    object of each match writes the distance field of each match

Notes
-----
.. warning::
   the coord field of the source in each match must be correct

Definition at line 28 of file setMatchDistance.py.

def setMatchDistance(matches):
    """Set the distance field of the matches in a match list to the distance in
    radians on the sky.
 
    Parameters
    ----------
    matches : `list` of `lsst.afw.table.ReferenceMatch`
        a list of matches, reads the coord field of the source and reference
        object of each match writes the distance field of each match
 
    Notes
    -----
    .. warning::
       the coord field of the source in each match must be correct
    """
    if len(matches) < 1:
        return
 
    sourceCoordKey = afwTable.CoordKey(matches[0].first.schema["coord"])
    refObjCoordKey = afwTable.CoordKey(matches[0].second.schema["coord"])
    for match in matches:
        sourceCoord = match.first.get(sourceCoordKey)
        refObjCoord = match.second.get(refObjCoordKey)
        match.distance = refObjCoord.separation(sourceCoord).asRadians()