def testWarnings(self):
"""Test that approximateWcs raises a UserWarning when it cannot achieve desired tolerance"""
radialTransform = afwGeom.makeRadialTransform([0, 2.0, 3.0])
wcs = afwGeom.makeModifiedWcs(pixelTransform=radialTransform, wcs=self.tanWcs,
modifyActualPixels=False)
with self.assertRaises(UserWarning):
approximateWcs(wcs=wcs, bbox=self.bbox, order=2)
def testWarnings(self):
"""Test that approximateWcs raises a UserWarning when it cannot achieve desired tolerance"""
radialTransform = afwGeom.makeRadialTransform([0, 2.0, 3.0])
wcs = afwGeom.makeModifiedWcs(pixelTransform=radialTransform,
wcs=self.tanWcs,
modifyActualPixels=False)
with self.assertRaises(UserWarning):
approximateWcs(wcs=wcs, bbox=self.bbox, order=2)
def doTest(self, name, transform, order=3, doPlot=False):
"""Add the specified distorting transform to a TAN WCS and fit it
The resulting WCS pixelToSky method acts as follows:
pixelToSky(transform.applyForward(pixels))
"""
wcs = afwGeom.makeModifiedWcs(pixelTransform=transform,
wcs=self.tanWcs,
modifyActualPixels=False)
fitWcs = approximateWcs(
wcs=wcs,
bbox=self.bbox,
order=order,
)
if doPlot:
self.plotWcs(wcs, fitWcs, self.bbox, transform)
msg = "ERROR: %s failed with order %s" % (name, order)
self.assertWcsAlmostEqualOverBBox(wcs,
fitWcs,
self.bbox,
maxDiffSky=0.001 *
afwGeom.arcseconds,
maxDiffPix=0.02,
msg=msg)
def getTanSipWcs(self, order=3, skyToleranceArcSec=0.001, pixelTolerance=0.01):
"""
Take an afw Detector and approximate its pixel-to-(Ra,Dec) transformation
with a TAN-SIP WCs.
Definition of the TAN-SIP WCS can be found in Shupe and Hook (2008)
http://fits.gsfc.nasa.gov/registry/sip/SIP_distortion_v1_0.pdf
@param order The order of the SIP polynomials to be fit to the
optical distortions [default: 3]
@param skyToleranceArcSec The maximum allowed error in the fitted world coordinates (in
arcseconds). [default: 0.001]
@param pixelTolerance The maximum allowed error in the fitted pixel coordinates.
[default: 0.02]
@returns tanSipWcs, an instantiation of lsst.afw.image's TanWcs class representing the WCS
of the detector with optical distortions parametrized by the SIP polynomials.
"""
bbox = self._detector.getBBox()
tanWcs = self.getTanWcs()
mockExposure = afwImage.ExposureF(bbox.getMaxX(), bbox.getMaxY())
mockExposure.setWcs(tanWcs)
mockExposure.setDetector(self._detector)
distortedWcs = afwImageUtils.getDistortedWcs(mockExposure.getInfo())
tanSipWcs = measAstrom.approximateWcs(
distortedWcs, bbox, order=order,
skyTolerance=skyToleranceArcSec*afwGeom.arcseconds,
pixelTolerance=pixelTolerance)
return tanSipWcs
def tanSipWcsFromDetector(afwDetector, afwCamera, obs_metadata, epoch,
order=3,
skyToleranceArcSec=0.001,
pixelTolerance=0.01):
"""
Take an afw Detector and approximate its pixel-to-(Ra,Dec) transformation
with a TAN-SIP WCs.
Definition of the TAN-SIP WCS can be found in Shupe and Hook (2008)
http://fits.gsfc.nasa.gov/registry/sip/SIP_distortion_v1_0.pdf
@param [in] afwDetector is an instantiation of afw.cameraGeom's Detector
class which characterizes the detector for which you wish to return th
WCS
@param [in] afwCamera is an instantiation of afw.cameraGeom's Camera
class which characterizes the camera containing afwDetector
@param [in] obs_metadata is an instantiation of ObservationMetaData
characterizing the telescope's current pointing
@param [in] epoch is the epoch in Julian years of the equinox against
which RA and Dec are measured
@param [in] order is the order of the SIP polynomials to be fit to the
optical distortions (default 3)
@param [in] skyToleranceArcSec is the maximum allowed error in the fitted
world coordinates (in arcseconds). Default 0.001
@param [in] pixelTolerance is the maximum allowed error in the fitted
pixel coordinates. Default 0.02
@param [out] tanSipWcs is an instantiation of afw.image's TanWcs class
representing the WCS of the detector with optical distortions parametrized
by the SIP polynomials.
"""
bbox = afwDetector.getBBox()
tanWcs = tanWcsFromDetector(afwDetector, afwCamera, obs_metadata, epoch)
mockExposure = afwImage.ExposureF(bbox.getMaxX(), bbox.getMaxY())
mockExposure.setWcs(tanWcs)
mockExposure.setDetector(afwDetector)
distortedWcs = afwImageUtils.getDistortedWcs(mockExposure.getInfo())
tanSipWcs = measAstrom.approximateWcs(distortedWcs, bbox,
order=order,
skyTolerance=skyToleranceArcSec*afwGeom.arcseconds,
pixelTolerance=pixelTolerance)
return tanSipWcs
def doTest(self, name, xyTransform, order=3, doPlot=False):
"""Create a DistortedTanWcs from the specified transform and fit it
"""
wcs = afwImage.DistortedTanWcs(self.tanWcs, xyTransform)
fitWcs = approximateWcs(
wcs = wcs,
bbox = self.bbox,
order=order,
)
if doPlot:
self.plotWcs(wcs, fitWcs, self.bbox, xyTransform)
msg = "ERROR: %s failed with order %s" % (name, order)
self.assertWcsNearlyEqualOverBBox(wcs, fitWcs, self.bbox,
maxDiffSky=0.001*afwGeom.arcseconds, maxDiffPix=0.02, msg=msg)
def getTanSipWcs(self,
order=3,
skyToleranceArcSec=0.001,
pixelTolerance=0.01):
"""
Take an afw Detector and approximate its pixel-to-(Ra,Dec) transformation
with a TAN-SIP WCs.
Definition of the TAN-SIP WCS can be found in Shupe and Hook (2008)
http://fits.gsfc.nasa.gov/registry/sip/SIP_distortion_v1_0.pdf
@param order The order of the SIP polynomials to be fit to the
optical distortions [default: 3]
@param skyToleranceArcSec The maximum allowed error in the fitted world coordinates (in
arcseconds). [default: 0.001]
@param pixelTolerance The maximum allowed error in the fitted pixel coordinates.
[default: 0.02]
@returns tanSipWcs, an instantiation of lsst.afw.image's TanWcs class representing the WCS
of the detector with optical distortions parametrized by the SIP polynomials.
"""
bbox = self._detector.getBBox()
tanWcs = self.getTanWcs()
mockExposure = afwImage.ExposureF(bbox.getMaxX(), bbox.getMaxY())
mockExposure.setWcs(tanWcs)
mockExposure.setDetector(self._detector)
distortedWcs = afwImageUtils.getDistortedWcs(mockExposure.getInfo())
tanSipWcs = measAstrom.approximateWcs(distortedWcs,
bbox,
order=order,
skyTolerance=skyToleranceArcSec *
afwGeom.arcseconds,
pixelTolerance=pixelTolerance)
return tanSipWcs
def doTest(self, name, xyTransform, order=3, doPlot=False):
"""Create a DistortedTanWcs from the specified transform and fit it
"""
wcs = afwImage.DistortedTanWcs(self.tanWcs, xyTransform)
fitWcs = approximateWcs(
wcs=wcs,
bbox=self.bbox,
order=order,
)
if doPlot:
self.plotWcs(wcs, fitWcs, self.bbox, xyTransform)
msg = "ERROR: %s failed with order %s" % (name, order)
self.assertWcsAlmostEqualOverBBox(wcs,
fitWcs,
self.bbox,
maxDiffSky=0.001 *
afwGeom.arcseconds,
maxDiffPix=0.02,
msg=msg)
def doTest(self, name, transform, order=3, doPlot=False):
"""Add the specified distorting transform to a TAN WCS and fit it
The resulting WCS pixelToSky method acts as follows:
pixelToSky(transform.applyForward(pixels))
"""
wcs = afwGeom.makeModifiedWcs(pixelTransform=transform,
wcs=self.tanWcs,
modifyActualPixels=False)
fitWcs = approximateWcs(
wcs=wcs,
bbox=self.bbox,
order=order,
)
if doPlot:
self.plotWcs(wcs, fitWcs, self.bbox, transform)
msg = "ERROR: %s failed with order %s" % (name, order)
self.assertWcsAlmostEqualOverBBox(wcs, fitWcs, self.bbox,
maxDiffSky=0.001*lsst.geom.arcseconds, maxDiffPix=0.02, msg=msg)
def testWarnings(self):
"""Test that approximateWcs raises a UserWarning when it cannot achieve desired tolerance"""
radialTransform = afwGeom.RadialXYTransform([0, 2.0, 3.0])
wcs = afwImage.DistortedTanWcs(self.tanWcs, radialTransform)
with self.assertRaises(UserWarning):
approximateWcs(wcs=wcs, bbox=self.bbox, order=2)
