def testLinearize(self):
for transform, invertible in (
(afwGeom.TransformPoint2ToPoint2(makeForwardPolyMap(2, 2)), False),
(afwGeom.makeIdentityTransform(), True),
(afwGeom.makeTransform(lsst.geom.AffineTransform(np.array([[3.0, -2.0], [2.0, -1.0]]))), True),
(afwGeom.makeRadialTransform([0.0, 8.0e-05, 0.0, -4.5e-12]), True),
):
self.checkLinearize(transform, invertible)
def setUp(self):
# Make fake sources
self.nSources = 10
self.bbox = geom.Box2I(geom.Point2I(0, 0),
geom.Extent2I(1024, 1153))
self.xyLoc = 100
dataset = measTests.TestDataset(self.bbox)
for srcIdx in range(self.nSources):
dataset.addSource(100000.0,
geom.Point2D(srcIdx*self.xyLoc,
srcIdx*self.xyLoc))
schema = dataset.makeMinimalSchema()
schema.addField("base_PixelFlags_flag", type="Flag")
schema.addField("base_PixelFlags_flag_offimage", type="Flag")
self.exposure, catalog = dataset.realize(
10.0, schema, randomSeed=1234)
for src in catalog:
src.setCoord(self.exposure.getWcs().pixelToSky(src.getCentroid()))
# Non-invertible WCS to test robustness to distortions.
# Coefficients transform (x - 1e-7*x^3 -> x, y -> y); see docs for PolyMap.
pixelCoeffs = np.array([[-1.0e-7, 1, 3, 0],
[1.0, 1, 1, 0],
[1.0, 2, 0, 1],
])
self.exposure.setWcs(afwGeom.makeModifiedWcs(
afwGeom.TransformPoint2ToPoint2(ast.PolyMap(pixelCoeffs, 2, options="IterInverse=1")),
self.exposure.wcs,
modifyActualPixels=False
))
# Convert to task required format
self.testDiaSources = catalog.asAstropy().to_pandas()
self.testDiaSources.rename(columns={"coord_ra": "ra",
"coord_dec": "decl"},
inplace=True,)
self.testDiaSources.loc[:, "ra"] = np.rad2deg(self.testDiaSources["ra"])
self.testDiaSources.loc[:, "decl"] = np.rad2deg(self.testDiaSources["decl"])
self.testDiaSources["ssObjectId"] = 0
# Grab a subset to treat as solar system objects
self.testSsObjects = self.testDiaSources[2:8].reset_index()
# Assign them ids starting from 1.
self.testSsObjects.loc[:, "ssObjectId"] = np.arange(
1, len(self.testSsObjects) + 1, dtype=int,)
self.testSsObjects["Err(arcsec)"] = np.ones(len(self.testSsObjects))
def makeSipIwcToPixel(metadata):
"""Make an IWC to pixel transform with SIP distortion from FITS-WCS metadata
This function is primarily intended for unit tests.
IWC is intermediate world coordinates, as described in the FITS papers.
Parameters
----------
metadata : lsst.daf.base.PropertySet
FITS metadata describing a WCS with inverse SIP coefficients
Returns
-------
lsst.afw.geom.TransformPoint2ToPoint2
Transform from IWC position to pixel position (zero-based)
in the forward direction. The inverse direction is not defined.
Notes
-----
The inverse SIP terms APn_m, BPn_m are polynomial coefficients x^n y^m
for computing transformed x, y respectively. If we call the resulting
polynomial inverseSipPolynomial, the returned transformation is:
pixelPosition = pixel origin + uv + inverseSipPolynomial(uv)
where uv = inverseCdMatrix * iwcPosition
"""
crpix = (metadata.getScalar("CRPIX1") - 1,
metadata.getScalar("CRPIX2") - 1)
pixelRelativeToAbsoluteMap = ast.ShiftMap(crpix)
cdMatrix = getCdMatrixFromMetadata(metadata)
cdMatrixMap = ast.MatrixMap(cdMatrix.copy())
coeffList = makeSipPolyMapCoeffs(metadata, "AP") + makeSipPolyMapCoeffs(
metadata, "BP")
coeffArr = np.array(coeffList, dtype=float)
sipPolyMap = ast.PolyMap(coeffArr, 2, "IterInverse=0")
iwcToPixelMap = cdMatrixMap.inverted().then(sipPolyMap).then(
pixelRelativeToAbsoluteMap)
return afwGeom.TransformPoint2ToPoint2(iwcToPixelMap)
def makeSipPixelToIwc(metadata):
"""Make a pixel to IWC transform with SIP distortion from FITS-WCS metadata
This function is primarily intended for unit tests.
IWC is intermediate world coordinates, as described in the FITS papers.
Parameters
----------
metadata : lsst.daf.base.PropertySet
FITS metadata describing a WCS with forward SIP coefficients
Returns
-------
lsst.afw.geom.TransformPoint2ToPoint2
Transform from pixel position (zero-based) to IWC position
in the forward direction. The inverse direction is not defined.
Notes
-----
The forward SIP terms An_m, Bn_m are polynomial coefficients x^n y^m
for computing transformed x, y respectively. If we call the resulting
polynomial sipPolynomial, the returned transformation is:
iwcPosition = cdMatrix * (dxy + sipPolynomial(dxy))
where dxy = pixelPosition - pixelOrigin
"""
crpix = (metadata.get("CRPIX1") - 1, metadata.get("CRPIX2") - 1)
pixelAbsoluteToRelativeMap = ast.ShiftMap(crpix).getInverse()
cdMatrix = getCdMatrixFromMetadata(metadata)
cdMatrixMap = ast.MatrixMap(cdMatrix.copy())
coeffList = makeSipPolyMapCoeffs(metadata, "A") + makeSipPolyMapCoeffs(
metadata, "B")
coeffArr = np.array(coeffList, dtype=float)
sipPolyMap = ast.PolyMap(coeffArr, 2, "IterInverse=0")
pixelToIwcMap = pixelAbsoluteToRelativeMap.then(sipPolyMap).then(
cdMatrixMap)
return afwGeom.TransformPoint2ToPoint2(pixelToIwcMap)