def testGetVectorValue(self):
"""Test if getVector() returns the expected value.
The test includes conformance to vector-angle conventions.
"""
for lon, lat, vector in [
(0.0 * degrees, 0.0 * degrees,
lsst.sphgeom.Vector3d(1.0, 0.0, 0.0)),
(90.0 * degrees, 0.0 * degrees,
lsst.sphgeom.Vector3d(0.0, 1.0, 0.0)),
(0.0 * degrees, 90.0 * degrees,
lsst.sphgeom.Vector3d(0.0, 0.0, 1.0)),
]:
for point in (
SpherePoint(lon, lat),
SpherePoint(lon.asDegrees(), lat.asDegrees(), degrees),
SpherePoint(lon.asRadians(), lat.asRadians(), radians),
):
newVector = point.getVector()
self.assertIsInstance(newVector, lsst.sphgeom.UnitVector3d)
for oldElement, newElement in zip(vector, newVector):
self.assertAlmostEqual(oldElement, newElement)
# Convert back to spherical.
newLon, newLat = SpherePoint(newVector)
self.assertAlmostEqual(newLon.asDegrees(), lon.asDegrees())
self.assertAlmostEqual(newLat.asDegrees(), lat.asDegrees())
# Try some un-normalized ones, too.
pointList = [
((0.0, 0.0), lsst.sphgeom.Vector3d(1.3, 0.0, 0.0)),
((90.0, 0.0), lsst.sphgeom.Vector3d(0.0, 1.2, 0.0)),
((0.0, 90.0), lsst.sphgeom.Vector3d(0.0, 0.0, 2.3)),
((0.0, 0.0), lsst.sphgeom.Vector3d(0.5, 0.0, 0.0)),
((90.0, 0.0), lsst.sphgeom.Vector3d(0.0, 0.7, 0.0)),
((0.0, 90.0), lsst.sphgeom.Vector3d(0.0, 0.0, 0.9)),
]
for lonLat, vector in pointList:
# Only convert from vector to spherical.
point = SpherePoint(vector)
newLon, newLat = point
self.assertAlmostEqual(lonLat[0], newLon.asDegrees())
self.assertAlmostEqual(lonLat[1], newLat.asDegrees())
vector = lsst.sphgeom.Vector3d(point.getVector())
self.assertAlmostEqual(1.0, vector.getSquaredNorm())
# Ill-defined points should be all NaN after normalization
cleanValues = [0.5, -0.3, 0.2]
badValues = [nan, inf, -inf]
for i in range(3):
for badValue in badValues:
values = cleanValues[:]
values[i] = badValue
nonFiniteVector = lsst.sphgeom.Vector3d(*values)
for element in SpherePoint(nonFiniteVector).getVector():
self.assertTrue(math.isnan(element))
def testGetVectorValue(self):
"""Test if getVector() returns the expected value.
The test includes conformance to vector-angle conventions.
"""
for lon, lat, vector in [
(0.0*degrees, 0.0*degrees, lsst.sphgeom.Vector3d(1.0, 0.0, 0.0)),
(90.0*degrees, 0.0*degrees, lsst.sphgeom.Vector3d(0.0, 1.0, 0.0)),
(0.0*degrees, 90.0*degrees, lsst.sphgeom.Vector3d(0.0, 0.0, 1.0)),
]:
for point in (
SpherePoint(lon, lat),
SpherePoint(lon.asDegrees(), lat.asDegrees(), degrees),
SpherePoint(lon.asRadians(), lat.asRadians(), radians),
):
newVector = point.getVector()
self.assertIsInstance(newVector, lsst.sphgeom.UnitVector3d)
for oldElement, newElement in zip(vector, newVector):
self.assertAlmostEqual(oldElement, newElement)
# Convert back to spherical.
newLon, newLat = SpherePoint(newVector)
self.assertAlmostEqual(newLon.asDegrees(), lon.asDegrees())
self.assertAlmostEqual(newLat.asDegrees(), lat.asDegrees())
# Try some un-normalized ones, too.
pointList = [
((0.0, 0.0), lsst.sphgeom.Vector3d(1.3, 0.0, 0.0)),
((90.0, 0.0), lsst.sphgeom.Vector3d(0.0, 1.2, 0.0)),
((0.0, 90.0), lsst.sphgeom.Vector3d(0.0, 0.0, 2.3)),
((0.0, 0.0), lsst.sphgeom.Vector3d(0.5, 0.0, 0.0)),
((90.0, 0.0), lsst.sphgeom.Vector3d(0.0, 0.7, 0.0)),
((0.0, 90.0), lsst.sphgeom.Vector3d(0.0, 0.0, 0.9)),
]
for lonLat, vector in pointList:
# Only convert from vector to spherical.
point = SpherePoint(vector)
newLon, newLat = point
self.assertAlmostEqual(lonLat[0], newLon.asDegrees())
self.assertAlmostEqual(lonLat[1], newLat.asDegrees())
vector = lsst.sphgeom.Vector3d(point.getVector())
self.assertAlmostEqual(1.0, vector.getSquaredNorm())
# Ill-defined points should be all NaN after normalization
cleanValues = [0.5, -0.3, 0.2]
badValues = [nan, inf, -inf]
for i in range(3):
for badValue in badValues:
values = cleanValues[:]
values[i] = badValue
nonFiniteVector = lsst.sphgeom.Vector3d(*values)
for element in SpherePoint(nonFiniteVector).getVector():
self.assertTrue(math.isnan(element))
def testToUnitXZY(self):
"""Test that the numpy-vectorized transformation from (lat, lon) to
(x, y, z) matches SpherePoint.getVector().
"""
for units in (degrees, radians):
scale = float(180.0 * degrees) / float(1.0 * units)
lon = scale * np.random.rand(5, 3)
lat = scale * (np.random.rand(5, 3) - 0.5)
x, y, z = SpherePoint.toUnitXYZ(longitude=lon,
latitude=lat,
units=units)
for i in range(lon.shape[0]):
for j in range(lon.shape[1]):
s = SpherePoint(lon[i, j], lat[i, j], units)
u1 = s.getVector()
u2 = lsst.sphgeom.UnitVector3d(x=x[i, j], y=y[i, j], z=z[i, j])
self.assertFloatsAlmostEqual(np.array(u1, dtype=float),
np.array(u2, dtype=float))
def computeAzAltFromBasePupil(vectorBase, vectorPupil):
"""Compute az/alt from a vector in the base frame
and the same vector in the pupil frame.
Parameters
----------
vectorBase : `iterable` of three `float`
3-dimensional vector in the :ref:`base frame
<lsst.cbp.base_frame>`.
vectorPupil : `iterable` of `float`
The same vector in the :ref:`pupil frame <lsst.cbp.pupil_frame>`.
This vector should be within 45 degrees or so of the optical axis
for accurate results.
Returns
-------
pupilAzAlt : `lsst.geom.SpherePoint`
Pointing of the pupil frame as :ref:`internal azimuth, altitude
<lsst.cbp.internal_angles>`.
Raises
------
ValueError
If vectorPupil x <= 0
Notes
-----
The magnitude of each vector is ignored, except that a reasonable
magnitude is required in order to compute an accurate unit vector.
"""
if vectorPupil[0] <= 0:
raise ValueError("vectorPupil x must be > 0: {}".format(vectorPupil))
# Compute telescope altitude using:
#
# base z = sin(alt) pupil x + cos(alt) pupil z
#
# One way to derive this is from the last row of an Euler rotation
# matrix listed in the comments for convertVectorFromBaseToPupil.
spBase = SpherePoint(Vector3d(*vectorBase))
spPupil = SpherePoint(Vector3d(*vectorPupil))
xb, yb, zb = spBase.getVector()
xp, yp, zp = spPupil.getVector()
factor = 1 / math.fsum((xp**2, zp**2))
addend1 = xp * zb
addend2 = zp * math.sqrt(math.fsum((xp**2, zp**2, -zb**2)))
if zp == 0:
sinAlt = zb / xp
else:
sinAlt = factor * (addend1 - addend2)
alt = math.asin(sinAlt) * radians
# Consider the spherical triangle connecting the telescope pointing
# (pupil frame x axis), the vector, and zenith (the base frame z axis).
# The length of all sides is known:
# - sideA is the side connecting the vector to the pupil frame x axis
# (since 0, 0 is a unit vector pointing along pupil frame x);
# - sideB is the side connecting telescope pointing to the zenith
# - sideC is the side connecting the vector to the zenith
#
# Solve for angleA, the angle between the sides at the zenith;
# that angle is the difference in azimuth between the telescope pointing
# and the azimuth of the base vector.
sideA = SpherePoint(0, 0, radians).separation(spPupil).asRadians()
sideB = math.pi / 2 - alt.asRadians()
sideC = math.pi / 2 - spBase[1].asRadians()
# sideA can be small or zero so use a half angle formula
# sides B and C will always be well away from 0 and 180 degrees
semiPerimeter = 0.5 * math.fsum((sideA, sideB, sideC))
sinHalfAngleA = math.sqrt(
math.sin(semiPerimeter - sideB) * math.sin(semiPerimeter - sideC) /
(math.sin(sideB) * math.sin(sideC)))
daz = 2 * math.asin(sinHalfAngleA) * radians
if spPupil[0].wrapCtr() > 0:
daz = -daz
az = spBase[0] + daz
global _RecordError
if _RecordError: # to study sources of numerical imprecision
global _ErrorLimitArcsec, _ErrorList
sp = SpherePoint(az, alt)
vectorBaseRT = convertVectorFromPupilToBase(vectorPupil, sp)
errorArcsec = SpherePoint(Vector3d(*vectorBaseRT)).separation(
SpherePoint(Vector3d(*vectorBase))).asArcseconds()
if errorArcsec > _ErrorLimitArcsec:
_ErrorList.append((errorArcsec, vectorBase, vectorPupil))
return SpherePoint(az, alt)
def trim(row):
coord = SpherePoint(row[self.config.raColName],
row[self.config.decColName], radians)
return region.contains(coord.getVector())
