def intersection(self, path):
"""
Return the intersection between the paths
Parameters
----------
path: GeoPath object
path to intersect
Returns
-------
point: GeoPoint
point of intersection between paths
"""
frame = self.positionA.frame
n_EA1_E, n_EA2_E = self.nvector_normals()
n_EB1_E, n_EB2_E = path.nvector_normals()
# Find the intersection between the two paths, n_EC_E:
n_EC_E_tmp = unit(cross(cross(n_EA1_E, n_EA2_E, axis=0),
cross(n_EB1_E, n_EB2_E, axis=0), axis=0),
norm_zero_vector=np.nan)
# n_EC_E_tmp is one of two solutions, the other is -n_EC_E_tmp. Select
# the one that is closet to n_EA1_E, by selecting sign from the dot
# product between n_EC_E_tmp and n_EA1_E:
n_EC_E = np.sign(dot(n_EC_E_tmp.T, n_EA1_E)) * n_EC_E_tmp
if np.any(np.isnan(n_EC_E)):
warnings.warn('Paths are Equal. Intersection point undefined. '
'NaN returned.')
lat_EC, long_EC = n_E2lat_lon(n_EC_E, frame.R_Ee)
return GeoPoint(lat_EC, long_EC, frame=frame)
def _cross_track_point(path, point):
"""Extend nvector package to find the projection point.
The projection point is the closest point on path to the given point.
Based on the nvector.cross_track_distance function.
http://www.navlab.net/nvector/
:param path: GeoPath
:param point: GeoPoint
"""
c_E = great_circle_normal(*path.nvector_normals())
n_EB_E = point.to_nvector().normal # type: np.array
c_EP_E = np.cross(c_E, n_EB_E, axis=0)
# Find intersection point C that is closest to point B
frame = path.positionA.frame
n_EA1_E = path.positionA.to_nvector(
).normal # should also be ok to use n_EB_C
n_EC_E_tmp = unit(np.cross(c_E, c_EP_E, axis=0), norm_zero_vector=np.nan)
n_EC_E = np.sign(np.dot(n_EC_E_tmp.T, n_EA1_E)) * n_EC_E_tmp
if np.any(np.isnan(n_EC_E)):
raise Exception(
'Paths are Equal. Intersection point undefined. NaN returned.')
lat_C, long_C = n_E2lat_lon(n_EC_E, frame.R_Ee)
return nv.GeoPoint(lat_C, long_C, frame=frame)
def to_geo_point(self):
"""
Converts n-vector to geo-point.
See also
--------
n_E2lat_lon, GeoPoint, ECEFvector, Pvector
"""
n_E = self.normal
latitude, longitude = n_E2lat_lon(n_E, R_Ee=self.frame.R_Ee)
return GeoPoint(latitude, longitude, self.z, self.frame)
def to_geo_point(self):
"""
Converts n-vector to geo-point.
See also
--------
n_E2lat_lon, GeoPoint, ECEFvector, Pvector
"""
n_E = self.normal
latitude, longitude = n_E2lat_lon(n_E, R_Ee=self.frame.R_Ee)
return GeoPoint(latitude, longitude, self.z, self.frame)
