lsst.meas.astrom.fitAffineWcs.TransformedSkyWcsMaker Class Reference

Public Member Functions
def	__init__ (self, inputSkyWcs)
def	makeWcs (self, crvalOffset, affMatrix)

Public Attributes
	frameDict
	frameIdxs
	frameMin
	frameMax
	mapFrom
	mapTo
	lastMapBeforeSky
	origin

Detailed Description

Convenience class for appending a shifting an input SkyWcs on sky and
appending an affine transform.

The class assumes that all frames are sequential and are mapped one to the
next.

Parameters
----------
input_sky_wcs : `lsst.afw.geom.SkyWcs`
    WCS to decompose and append affine matrix and shift in on sky
    location to.

Definition at line 247 of file fitAffineWcs.py.

Constructor & Destructor Documentation

__init__()

def lsst.meas.astrom.fitAffineWcs.TransformedSkyWcsMaker.__init__	(		self,
			inputSkyWcs
	)

Definition at line 261 of file fitAffineWcs.py.

    def __init__(self, inputSkyWcs):
        self.frameDict = inputSkyWcs.getFrameDict()
 
        # Grab the order of the frames by index.
        # TODO: DM-20825
        #    Change the frame the transform is appended to to be explicitly
        #    the FIELD_ANGLE->IWC transform. Requires related tickets to be
        #    completed.
        domains = self.frameDict.getAllDomains()
        self.frameIdxs = np.sort([self.frameDict.getIndex(domain)
                                  for domain in domains])
        self.frameMin = np.min(self.frameIdxs)
        self.frameMax = np.max(self.frameIdxs)
 
        # Find frame just before the final mapping to sky and store those
        # indices and mappings for later.
        self.mapFrom = self.frameMax - 2
        if self.mapFrom < self.frameMin:
            self.mapFrom = self.frameMin
        self.mapTo = self.frameMax - 1
        if self.mapTo <= self.mapFrom:
            self.mapTo = self.frameMax
        self.lastMapBeforeSky = self.frameDict.getMapping(
            self.mapFrom, self.mapTo)
 
        # Get the original WCS sky location.
 
        self.origin = inputSkyWcs.getSkyOrigin()
 

Member Function Documentation

makeWcs()

def lsst.meas.astrom.fitAffineWcs.TransformedSkyWcsMaker.makeWcs	(		self,
			crvalOffset,
			affMatrix
	)

Apply a shift and affine transform to the WCS internal to this
class.

A new SkyWcs with these transforms applied is returns.

Parameters
----------
crval_shift : `numpy.ndarray`, (2,)
    Shift in radians to apply to the Wcs origin/crvals.
aff_matrix : 'numpy.ndarray', (3, 3)
    Affine matrix to apply to the mapping/transform to add to the
    WCS.

Returns
-------
outputWcs : `lsst.afw.geom.SkyWcs`
    Wcs with a final shift and affine transform applied.

Definition at line 290 of file fitAffineWcs.py.

    def makeWcs(self, crvalOffset, affMatrix):
        """Apply a shift and affine transform to the WCS internal to this
        class.
 
        A new SkyWcs with these transforms applied is returns.
 
        Parameters
        ----------
        crval_shift : `numpy.ndarray`, (2,)
            Shift in radians to apply to the Wcs origin/crvals.
        aff_matrix : 'numpy.ndarray', (3, 3)
            Affine matrix to apply to the mapping/transform to add to the
            WCS.
 
        Returns
        -------
        outputWcs : `lsst.afw.geom.SkyWcs`
            Wcs with a final shift and affine transform applied.
        """
        # Create a WCS that only maps from IWC to Sky with the shifted
        # Sky origin position. This is simply the final undistorted tangent
        # plane to sky. The PIXELS to SKY map will be become our IWC to SKY
        # map and gives us our final shift position.
        iwcsToSkyWcs = makeSkyWcs(
            Point2D(0., 0.),
            self.origin.offset(crvalOffset[0] * degrees,
                               crvalOffset[1] * arcseconds),
            np.array([[1., 0.], [0., 1.]]))
        iwcToSkyMap = iwcsToSkyWcs.getFrameDict().getMapping("PIXELS", "SKY")
 
        # Append a simple affine Matrix transform to the current to the
        # second to last frame mapping. e.g. the one just before IWC to SKY.
        newMapping = self.lastMapBeforeSky.then(astshim.MatrixMap(affMatrix))
 
        # Create a new frame dict starting from the input_sky_wcs's first
        # frame. Append the correct mapping created above and our new on
        # sky location.
        outputFrameDict = astshim.FrameDict(
            self.frameDict.getFrame(self.frameMin))
        for frameIdx in self.frameIdxs:
            if frameIdx == self.mapFrom:
                outputFrameDict.addFrame(
                    self.mapFrom,
                    newMapping,
                    self.frameDict.getFrame(self.mapTo))
            elif frameIdx >= self.mapTo:
                continue
            else:
                outputFrameDict.addFrame(
                    frameIdx,
                    self.frameDict.getMapping(frameIdx, frameIdx + 1),
                    self.frameDict.getFrame(frameIdx + 1))
        # Append the final sky frame to the frame dict.
        outputFrameDict.addFrame(
            self.frameMax - 1,
            iwcToSkyMap,
            iwcsToSkyWcs.getFrameDict().getFrame("SKY"))
 
        return SkyWcs(outputFrameDict)

Member Data Documentation

frameDict

lsst.meas.astrom.fitAffineWcs.TransformedSkyWcsMaker.frameDict

Definition at line 262 of file fitAffineWcs.py.

frameIdxs

lsst.meas.astrom.fitAffineWcs.TransformedSkyWcsMaker.frameIdxs

Definition at line 270 of file fitAffineWcs.py.

frameMax

lsst.meas.astrom.fitAffineWcs.TransformedSkyWcsMaker.frameMax

Definition at line 273 of file fitAffineWcs.py.

frameMin

lsst.meas.astrom.fitAffineWcs.TransformedSkyWcsMaker.frameMin

Definition at line 272 of file fitAffineWcs.py.

lastMapBeforeSky

lsst.meas.astrom.fitAffineWcs.TransformedSkyWcsMaker.lastMapBeforeSky

Definition at line 283 of file fitAffineWcs.py.

mapFrom

lsst.meas.astrom.fitAffineWcs.TransformedSkyWcsMaker.mapFrom

Definition at line 277 of file fitAffineWcs.py.

mapTo

lsst.meas.astrom.fitAffineWcs.TransformedSkyWcsMaker.mapTo

Definition at line 280 of file fitAffineWcs.py.

origin

lsst.meas.astrom.fitAffineWcs.TransformedSkyWcsMaker.origin

Definition at line 288 of file fitAffineWcs.py.

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The documentation for this class was generated from the following file:

• /j/snowflake/release/lsstsw/stack/0.4.3/Linux64/meas_astrom/21.0.0-4-g591bb35+a9c1acf22d/python/lsst/meas/astrom/fitAffineWcs.py