def testOffsetValue(self):
"""Test if offset() returns the expected value.
"""
# This should cover arcs over the meridian, across the pole, etc.
for lon1, lat1 in self._dataset:
point1 = SpherePoint(lon1, lat1)
if point1.atPole():
continue
for lon2, lat2 in self._dataset:
if lon1 == lon2 and lat1 == lat2:
continue
point2 = SpherePoint(lon2, lat2)
bearing = point1.bearingTo(point2)
distance = point1.separation(point2)
newPoint = point1.offset(bearing, distance)
self.assertIsInstance(newPoint, SpherePoint)
if point1.isFinite() and point2.isFinite():
if not point2.atPole():
self.assertAnglesAlmostEqual(
point2.getLongitude(), newPoint.getLongitude())
self.assertAnglesAlmostEqual(
point2.getLatitude(), newPoint.getLatitude())
else:
self.assertTrue(math.isnan(
newPoint.getLongitude().asRadians()))
self.assertTrue(math.isnan(
newPoint.getLatitude().asRadians()))
# Test precision near the poles
lon = 123.0*degrees
almostPole = SpherePoint(lon, self.nextDown(90.0*degrees))
goSouth = almostPole.offset(-90.0*degrees, 90.0*degrees)
self.assertAnglesAlmostEqual(lon, goSouth.getLongitude())
self.assertAnglesAlmostEqual(0.0*degrees, goSouth.getLatitude())
goEast = almostPole.offset(0.0*degrees, 90.0*degrees)
self.assertAnglesAlmostEqual(lon + 90.0*degrees, goEast.getLongitude())
self.assertAnglesAlmostEqual(0.0*degrees, goEast.getLatitude())
def testOffsetError(self):
"""Test if offset() correctly handles invalid input.
"""
northPole = SpherePoint(0.0*degrees, 90.0*degrees)
southPole = SpherePoint(0.0*degrees, -90.0*degrees)
nonSingularity = SpherePoint(0.0*degrees, 45.0*degrees)
with self.assertRaises(pexEx.DomainError):
northPole.offset(-90.0*degrees, 10.0*degrees)
with self.assertRaises(pexEx.DomainError):
southPole.offset(90.0*degrees, 0.1*degrees)
with self.assertRaises(pexEx.InvalidParameterError):
nonSingularity.offset(90.0*degrees, -0.1*degrees)
def testOffsetValue(self):
"""Test if offset() returns the expected value.
"""
# This should cover arcs over the meridian, across the pole, etc.
for lon1, lat1 in self._dataset:
point1 = SpherePoint(lon1, lat1)
for lon2, lat2 in self._dataset:
if lon1 == lon2 and lat1 == lat2:
continue
point2 = SpherePoint(lon2, lat2)
bearing = point1.bearingTo(point2)
distance = point1.separation(point2)
# offsetting point1 by bearing and distance should produce the same result as point2
newPoint = point1.offset(bearing, distance)
self.assertIsInstance(newPoint, SpherePoint)
self.assertSpherePointsAlmostEqual(point2, newPoint)
if newPoint.atPole():
self.assertAnglesAlmostEqual(newPoint.getLongitude(),
0 * degrees)
# measuring the separation and bearing from point1 to the new point
# should produce the requested separation and bearing
measuredDistance = point1.separation(newPoint)
self.assertAnglesAlmostEqual(measuredDistance, distance)
if abs(measuredDistance.asDegrees() - 180) > 1e-5:
# The two points are not opposite each other on the sphere,
# so the bearing has a well defined value
measuredBearing = point1.bearingTo(newPoint)
self.assertAnglesAlmostEqual(measuredBearing, bearing)
# offset by a negative amount in the opposite direction should produce the same result
newPoint2 = point1.offset(bearing + 180 * degrees, -distance)
self.assertIsInstance(newPoint2, SpherePoint)
# check angular separation (longitude is checked below)
self.assertSpherePointsAlmostEqual(newPoint, newPoint2)
if point1.isFinite() and point2.isFinite():
if not point2.atPole():
self.assertAnglesAlmostEqual(point2.getLongitude(),
newPoint.getLongitude())
self.assertAnglesAlmostEqual(point2.getLongitude(),
newPoint2.getLongitude())
self.assertAnglesAlmostEqual(point2.getLatitude(),
newPoint.getLatitude())
self.assertAnglesAlmostEqual(point2.getLatitude(),
newPoint2.getLatitude())
else:
self.assertTrue(
math.isnan(newPoint.getLongitude().asRadians()))
self.assertTrue(
math.isnan(newPoint2.getLongitude().asRadians()))
self.assertTrue(
math.isnan(newPoint.getLatitude().asRadians()))
self.assertTrue(
math.isnan(newPoint2.getLatitude().asRadians()))
# Test precision near the poles
lon = 123.0 * degrees
almostPole = SpherePoint(lon, self.nextDown(90.0 * degrees))
goSouth = almostPole.offset(-90.0 * degrees, 90.0 * degrees)
self.assertAnglesAlmostEqual(lon, goSouth.getLongitude())
self.assertAnglesAlmostEqual(0.0 * degrees, goSouth.getLatitude())
goEast = almostPole.offset(0.0 * degrees, 90.0 * degrees)
self.assertAnglesAlmostEqual(lon + 90.0 * degrees,
goEast.getLongitude())
self.assertAnglesAlmostEqual(0.0 * degrees, goEast.getLatitude())
