lsst.skymap.detail.wcsFactory.WcsFactory Class Reference

Inheritance diagram for lsst.skymap.detail.wcsFactory.WcsFactory:

Public Member Functions
def	__init__
def	makeWcs

Private Attributes
	_pixelScaleDeg
	_projection
	_rotation
	_cdMatrix
	_ctypes

Detailed Description

A factory for creating Wcs objects for the sky tiles.

Definition at line 29 of file wcsFactory.py.

Constructor & Destructor Documentation

def lsst.skymap.detail.wcsFactory.WcsFactory.__init__	(		self,
			pixelScale,
			projection,
			rotation = 0*afwGeom.radians
	)

Make a WcsFactory

@param[in] pixelScale: desired scale, as sky/pixel, an afwGeom.Angle
@param[in] projection: FITS-standard 3-letter name of projection, e.g.:
    TAN (tangent), STG (stereographic), MOL (Mollweide's), AIT (Hammer-Aitoff)
    see Representations of celestial coordinates in FITS (Calabretta and Greisen, 2002)
@param[in] rotation:   Rotation relative to cardinal, as an lsst.afw.geom.Angle

Definition at line 32 of file wcsFactory.py.

    def __init__(self, pixelScale, projection, rotation=0*afwGeom.radians):
        """Make a WcsFactory
        
        @param[in] pixelScale: desired scale, as sky/pixel, an afwGeom.Angle
        @param[in] projection: FITS-standard 3-letter name of projection, e.g.:
            TAN (tangent), STG (stereographic), MOL (Mollweide's), AIT (Hammer-Aitoff)
            see Representations of celestial coordinates in FITS (Calabretta and Greisen, 2002)
        @param[in] rotation:   Rotation relative to cardinal, as an lsst.afw.geom.Angle
        """
        if len(projection) != 3:
            raise RuntimeError("projection=%r; must have length 3" % (projection,))
        self._pixelScaleDeg = pixelScale.asDegrees()
        self._projection = str(projection)
        self._rotation = rotation
        cosTerm = self._pixelScaleDeg * math.cos(rotation.asRadians())
        sinTerm = self._pixelScaleDeg * math.sin(rotation.asRadians())
        self._cdMatrix = {"CD1_1": -cosTerm,
                          "CD2_1": sinTerm,
                          "CD1_2": sinTerm,
                          "CD2_2": cosTerm,
                          }
        self._ctypes = [("%-5s%3s" % (("RA", "DEC")[i], self._projection)).replace(" ", "-")
            for i in range(2)]