lsst.skymap.equatSkyMap.EquatSkyMap Class Reference

Inheritance diagram for lsst.skymap.equatSkyMap.EquatSkyMap:

Public Member Functions
def	__init__
def	__getstate__
def	__setstate__
def	getVersion

Static Public Attributes
	ConfigClass = EquatSkyMapConfig

Static Private Attributes
tuple	_version = (1, 0)

Detailed Description

Equatorial sky map pixelization, e.g. for SDSS stripe 82 image data.
    
EquatSkyMap represents an equatorial band of sky divided along declination into overlapping tracts.

Definition at line 45 of file equatSkyMap.py.

Constructor & Destructor Documentation

def lsst.skymap.equatSkyMap.EquatSkyMap.__init__	(		self,
			config = None
	)

Construct a EquatSkyMap

@param[in] config: an instance of self.ConfigClass; if None the default config is used

Definition at line 53 of file equatSkyMap.py.

    def __init__(self, config=None):
        """Construct a EquatSkyMap

        @param[in] config: an instance of self.ConfigClass; if None the default config is used
        """
        BaseSkyMap.__init__(self, config)
    
        decRange = tuple(afwGeom.Angle(dr, afwGeom.degrees) for dr in self.config.decRange)
        midDec = (decRange[0] +decRange[1]) / 2.0
        tractWidthRA = afwGeom.Angle(360.0 / self.config.numTracts, afwGeom.degrees)
        tractOverlap = afwGeom.Angle(self.config.tractOverlap, afwGeom.degrees)

        for id in range(self.config.numTracts):
            begRA = tractWidthRA * id
            endRA = begRA + tractWidthRA
            vertexCoordList = (
                afwCoord.IcrsCoord(begRA, decRange[0]),
                afwCoord.IcrsCoord(endRA, decRange[0]),
                afwCoord.IcrsCoord(endRA, decRange[1]),
                afwCoord.IcrsCoord(begRA, decRange[1]),
            )

            midRA = begRA + tractWidthRA / 2.0
            ctrCoord = afwCoord.IcrsCoord(midRA, midDec)
            
            # CRVal must have Dec=0 for symmetry about the equator
            crValCoord = afwCoord.IcrsCoord(midRA, afwGeom.Angle(0.0))

            # make initial WCS; don't worry about crPixPos because TractInfo will shift it as required
            wcs = self._wcsFactory.makeWcs(crPixPos=afwGeom.Point2D(0,0), crValCoord=crValCoord)
                
            self._tractInfoList.append(TractInfo(
                id = id,
                patchInnerDimensions = self.config.patchInnerDimensions,
                patchBorder = self.config.patchBorder,
                ctrCoord = ctrCoord,
                vertexCoordList = vertexCoordList,
                tractOverlap = tractOverlap,
                wcs = wcs,
            ))