def test_tan_sip_wcs(self):
"""
Test that getTanSipWcs works by fitting a TAN WCS and a TAN-SIP WCS to
the a detector with distortions and verifying that the TAN-SIP WCS better approximates
the truth.
"""
arcsec_per_radian = 180.0*3600.0/np.pi
tanWcs = self.wcs.getTanWcs()
tanSipWcs = self.wcs.getTanSipWcs()
tanWcsRa = []
tanWcsDec = []
tanSipWcsRa = []
tanSipWcsDec = []
xPixList = []
yPixList = []
for xx in np.arange(0.0, 4001.0, 1000.0):
for yy in np.arange(0.0, 4001.0, 1000.0):
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 = 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.wcs._camera.raDecFromPixelCoords(xPixList, yPixList,
[self.wcs._chip_name]*len(xPixList))
for rrTest, ddTest, rrTan, ddTan, rrSip, ddSip in \
zip(raTest, decTest, tanWcsRa, tanWcsDec, tanSipWcsRa, tanSipWcsDec):
pp = CelestialCoord(rrTest*galsim.radians, ddTest*galsim.radians)
distTan = \
pp.distanceTo(CelestialCoord(rrTan*galsim.radians, ddTan*galsim.radians))/galsim.arcsec
distSip = \
pp.distanceTo(CelestialCoord(rrSip*galsim.radians, ddSip*galsim.radians))/galsim.arcsec
msg = 'error in TAN WCS %e arcsec; error in TAN-SIP WCS %e arcsec' % (distTan, distSip)
self.assertLess(distSip, 0.001, msg=msg)
self.assertGreater(distTan-distSip, 1.0e-10, msg=msg)
def test_tan_sip_wcs(self):
"""
Test that getTanSipWcs works by fitting a TAN WCS and a TAN-SIP WCS to
the a detector with distortions and verifying that the TAN-SIP WCS better approximates
the truth.
"""
arcsec_per_radian = 180.0*3600.0/np.pi
tanWcs = self.wcs.getTanWcs()
tanSipWcs = self.wcs.getTanSipWcs()
tanWcsRa = []
tanWcsDec = []
tanSipWcsRa = []
tanSipWcsDec = []
xPixList = []
yPixList = []
for xx in np.arange(0.0, 4001.0, 1000.0):
for yy in np.arange(0.0, 4001.0, 1000.0):
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 = 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.wcs._camera.raDecFromPixelCoords(xPixList, yPixList,
[self.wcs._chip_name]*len(xPixList))
for rrTest, ddTest, rrTan, ddTan, rrSip, ddSip in \
zip(raTest, decTest, tanWcsRa, tanWcsDec, tanSipWcsRa, tanSipWcsDec):
pp = CelestialCoord(rrTest*galsim.radians, ddTest*galsim.radians)
distTan = \
pp.distanceTo(CelestialCoord(rrTan*galsim.radians, ddTan*galsim.radians))/galsim.arcsec
distSip = \
pp.distanceTo(CelestialCoord(rrSip*galsim.radians, ddSip*galsim.radians))/galsim.arcsec
msg = 'error in TAN WCS %e arcsec; error in TAN-SIP WCS %e arcsec' % (distTan, distSip)
self.assertLess(distSip, 0.001, msg=msg)
self.assertGreater(distTan-distSip, 1.0e-10, msg=msg)
def test_tan_wcs(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.
"""
start = time.clock()
xPixList = []
yPixList = []
tanWcs = self.wcs.getTanWcs()
wcsRa = []
wcsDec = []
for xx in np.arange(0.0, 4001.0, 1000.0):
for yy in np.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 = np.radians(np.array(wcsRa))
wcsDec = np.radians(np.array(wcsDec))
xPixList = np.array(xPixList)
yPixList = np.array(yPixList)
raTest, decTest = \
self.wcs._camera.raDecFromTanPixelCoords(xPixList, yPixList,
[self.wcs._chip_name]*len(xPixList))
for rr1, dd1, rr2, dd2 in zip(raTest, decTest, wcsRa, wcsDec):
pp = CelestialCoord(rr1*galsim.radians, dd1*galsim.radians)
dist = \
pp.distanceTo(CelestialCoord(rr2*galsim.radians, dd2*galsim.radians))/galsim.arcsec
msg = 'error in tanWcs was %e arcsec' % dist
self.assertLess(dist, 0.001, msg=msg)
print 'time to run %s = %e sec' % (funcname(), time.clock()-start)
