def testTanSipWcs(self):
"""
Test that tanSipWcsFromDetector works by fitting a TAN WCS and a TAN-SIP WCS to
a detector with distortions and verifying that the TAN-SIP WCS better approximates
the truth.
"""
tanWcs = tanWcsFromDetector(self.detector.getName(), self.camera_wrapper,
self.obs, self.epoch)
tanSipWcs = tanSipWcsFromDetector(self.detector.getName(), self.camera_wrapper,
self.obs, self.epoch)
tanWcsRa = []
tanWcsDec = []
tanSipWcsRa = []
tanSipWcsDec = []
xPixList = []
yPixList = []
for xx in np.arange(0.0, 4001.0, 100.0):
for yy in np.arange(0.0, 4001.0, 100.0):
xPixList.append(xx)
yPixList.append(yy)
pt = afwGeom.Point2D(xx, yy)
skyPt = tanWcs.pixelToSky(pt).getPosition(LsstGeom.degrees)
tanWcsRa.append(skyPt.getX())
tanWcsDec.append(skyPt.getY())
skyPt = tanSipWcs.pixelToSky(pt).getPosition(LsstGeom.degrees)
tanSipWcsRa.append(skyPt.getX())
tanSipWcsDec.append(skyPt.getY())
tanWcsRa = np.radians(np.array(tanWcsRa))
tanWcsDec = np.radians(np.array(tanWcsDec))
tanSipWcsRa = np.radians(np.array(tanSipWcsRa))
tanSipWcsDec = np.radians(np.array(tanSipWcsDec))
xPixList = np.array(xPixList)
yPixList = np.array(yPixList)
(raTest,
decTest) = self.camera_wrapper._raDecFromPixelCoords(xPixList, yPixList,
[self.detector.getName()]*len(xPixList),
obs_metadata=self.obs,
epoch=self.epoch)
tanDistanceList = arcsecFromRadians(haversine(raTest, decTest, tanWcsRa, tanWcsDec))
tanSipDistanceList = arcsecFromRadians(haversine(raTest, decTest, tanSipWcsRa, tanSipWcsDec))
maxDistanceTan = tanDistanceList.max()
maxDistanceTanSip = tanSipDistanceList.max()
msg = 'max error in TAN WCS %e arcsec; in TAN-SIP %e arcsec' % (maxDistanceTan, maxDistanceTanSip)
self.assertLess(maxDistanceTanSip, 0.01, msg=msg)
self.assertGreater(maxDistanceTan-maxDistanceTanSip, 1.0e-10, msg=msg)
def testTanSipWcs(self):
"""
Test that tanSipWcsFromDetector works by fitting a TAN WCS and a TAN-SIP WCS to
a detector with distortions and verifying that the TAN-SIP WCS better approximates
the truth.
"""
tanWcs = tanWcsFromDetector(self.detector, self.camera, self.obs, self.epoch)
tanSipWcs = tanSipWcsFromDetector(self.detector, self.camera, self.obs, self.epoch)
tanWcsRa = []
tanWcsDec = []
tanSipWcsRa = []
tanSipWcsDec = []
xPixList = []
yPixList = []
for xx in numpy.arange(0.0, 4001.0, 100.0):
for yy in numpy.arange(0.0, 4001.0, 100.0):
xPixList.append(xx)
yPixList.append(yy)
pt = afwGeom.Point2D(xx ,yy)
skyPt = tanWcs.pixelToSky(pt).getPosition()
tanWcsRa.append(skyPt.getX())
tanWcsDec.append(skyPt.getY())
skyPt = tanSipWcs.pixelToSky(pt).getPosition()
tanSipWcsRa.append(skyPt.getX())
tanSipWcsDec.append(skyPt.getY())
tanWcsRa = numpy.radians(numpy.array(tanWcsRa))
tanWcsDec = numpy.radians(numpy.array(tanWcsDec))
tanSipWcsRa = numpy.radians(numpy.array(tanSipWcsRa))
tanSipWcsDec = numpy.radians(numpy.array(tanSipWcsDec))
xPixList = numpy.array(xPixList)
yPixList = numpy.array(yPixList)
raTest, decTest = _raDecFromPixelCoords(xPixList, yPixList,
[self.detector.getName()]*len(xPixList),
camera=self.camera, obs_metadata=self.obs,
epoch=self.epoch)
tanDistanceList = arcsecFromRadians(haversine(raTest, decTest, tanWcsRa, tanWcsDec))
tanSipDistanceList = arcsecFromRadians(haversine(raTest, decTest, tanSipWcsRa, tanSipWcsDec))
maxDistanceTan = tanDistanceList.max()
maxDistanceTanSip = tanSipDistanceList.max()
msg = 'max error in TAN WCS %e arcsec; in TAN-SIP %e arcsec' % (maxDistanceTan, maxDistanceTanSip)
self.assertLess(maxDistanceTanSip, 0.01, msg=msg)
self.assertGreater(maxDistanceTan-maxDistanceTanSip, 1.0e-10, msg=msg)
def testTanWcs(self):
"""
Test method to return a Tan WCS by generating a bunch of pixel coordinates
in the undistorted TAN-PIXELS coordinate system. Then, use sims_coordUtils
to convert those pixel coordinates into RA and Dec. Compare these to the
RA and Dec returned by the WCS. Demand agreement to witin 0.001 arcseconds.
Note: if you use a bigger camera, it is possible to have disagreements of
order a few milliarcseconds.
"""
detector = self.camera[0]
xPixList = []
yPixList = []
tanWcs = tanWcsFromDetector(detector, self.camera, self.obs, self.epoch)
wcsRa = []
wcsDec = []
for xx in numpy.arange(0.0, 4001.0, 1000.0):
for yy in numpy.arange(0.0, 4001.0, 1000.0):
xPixList.append(xx)
yPixList.append(yy)
pt = afwGeom.Point2D(xx ,yy)
skyPt = tanWcs.pixelToSky(pt).getPosition()
wcsRa.append(skyPt.getX())
wcsDec.append(skyPt.getY())
wcsRa = numpy.radians(numpy.array(wcsRa))
wcsDec = numpy.radians(numpy.array(wcsDec))
xPixList = numpy.array(xPixList)
yPixList = numpy.array(yPixList)
raTest, decTest = _raDecFromPixelCoords(xPixList, yPixList,
[detector.getName()]*len(xPixList),
camera=self.camera, obs_metadata=self.obs,
epoch=self.epoch)
distanceList = arcsecFromRadians(haversine(raTest, decTest, wcsRa, wcsDec))
maxDistance = distanceList.max()
msg = 'maxError in tanWcs was %e ' % maxDistance
self.assertTrue(maxDistance<0.001, msg=msg)
