Coverage for pygeodesy/geodesicx/gxline.py: 91%
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« prev ^ index » next coverage.py v7.6.1, created at 2025-09-09 13:03 -0400
2# -*- coding: utf-8 -*-
4u'''A pure Python version of I{Karney}'s C++ class U{GeodesicLineExact
5<https://GeographicLib.SourceForge.io/C++/doc/classGeographicLib_1_1GeodesicLineExact.html>}.
7Class L{GeodesicLineExact} follows the naming, methods and return
8values from class C{GeodesicLine} from I{Karney}'s Python U{geographiclib
9<https://GeographicLib.SourceForge.io/1.52/python/index.html>}.
11Copyright (C) U{Charles Karney<mailto:Karney@Alum.MIT.edu>} (2008-2023)
12and licensed under the MIT/X11 License. For more information, see the
13U{GeographicLib<https://GeographicLib.SourceForge.io>} documentation.
14'''
15# make sure int/int division yields float quotient
16from __future__ import division as _; del _ # noqa: E702 ;
18# A copy of comments from Karney's C{GeodesicLineExact.cpp}:
19#
20# This is a reformulation of the geodesic problem. The
21# notation is as follows:
22# - at a general point (no suffix or 1 or 2 as suffix)
23# - phi = latitude
24# - lambda = longitude
25# - beta = latitude on auxiliary sphere
26# - omega = longitude on auxiliary sphere
27# - alpha = azimuth of great circle
28# - sigma = arc length along great circle
29# - s = distance
30# - tau = scaled distance (= sigma at multiples of PI/2)
31# - at northwards equator crossing
32# - beta = phi = 0
33# - omega = lambda = 0
34# - alpha = alpha0
35# - sigma = s = 0
36# - a 12 suffix means a difference, e.g., s12 = s2 - s1.
37# - s and c prefixes mean sin and cos
39# from pygeodesy.basics import _xinstanceof # _MODS
40from pygeodesy.constants import NAN, _EPSqrt as _TOL, \
41 _copysign_1_0, isfinite, \
42 _0_0, _1_0, _180_0, _360_0, \
43 _2__PI # PYCHOK used!
44from pygeodesy.errors import _xError, _xkwds_pop2
45# from pygeodesy.fmath import fremainder # from .karney
46from pygeodesy.fsums import fsumf_, fsum1f_
47from pygeodesy.geodesicx.gxbases import _cosSeries, _GeodesicBase, \
48 _sincos12, _sin1cos2, \
49 _sinf1cos2d, _TINY, _toNAN
50# from pygeodesy.geodesicw import _Intersecant2 # _MODS
51from pygeodesy.lazily import _ALL_DOCS, _ALL_MODS as _MODS
52from pygeodesy.karney import _around, _atan2d, Caps, GDict, _fix90, \
53 _K_2_0, _llz2gl, _norm2, _norm180, \
54 _sincos2, _sincos2d, fremainder
55from pygeodesy.props import Property_RO, property_ROver, _update_all
56from pygeodesy.utily import atan2, atan2d as _atan2d_reverse, sincos2
58from math import degrees, fabs, radians
60__all__ = ()
61__version__ = '25.09.09'
63_glXs = [] # instances of C{[_]GeodesicLineExact} to be updated
66def _update_glXs(gX): # see GeodesicExact.C4order and -._ef_reset_k2
67 '''(INTERNAL) Zap cached/memoized C{Property[_RO]}s of
68 any L{GeodesicLineExact} instances tied to the given
69 L{GeodesicExact} instance B{C{gX}}.
70 '''
71 _xGeodesicExact(gX=gX)
72 for glX in _glXs: # PYCHOK use weakref?
73 if glX._gX is gX:
74 _update_all(glX)
77def _xGeodesicExact(**gX):
78 '''(INTERNAL) Check a L{GeodesicExact} instance.
79 '''
80 _MODS.basics._xinstanceof(_MODS.geodesicx.GeodesicExact, **gX)
83class _GeodesicLineExact(_GeodesicBase):
84 '''(INTERNAL) Base class for L{GeodesicLineExact}.
85 '''
86 _a13 = _s13 = NAN
87# _azi1 = _0_0
88 _caps = Caps._AZIMUTH_LATITUDE_LONG_UNROLL
89# _cchi1 = NAN
90# _dn1 = NAN
91 _gX = None # Exact only
92# _k2 = NAN
93# _lat1 = _lon1 = _0_0
94# _salp0 = _calp0 = NAN
95# _salp1 = _calp1 = NAN
96# _somg1 = _comg1 = NAN
97# _ssig1 = _csig1 = NAN
98# _toNAN = False
100 def __init__(self, gX, lat1, lon1, azi1, caps, **name_):
101 '''(INTERNAL) New C{[_]GeodesicLineExact} instance.
102 '''
103# _xGeodesicExact(gX=gX)
104 if azi1 is None: # see GeodesicExact.InverseLine
105 (salp1, calp1), name_ = _xkwds_pop2(name_, _s_calp1=(_0_0, _1_0))
106 azi1 = _atan2d(salp1, calp1)
107 else: # guard against salp0 underflow, convert -0 to +0
108 azi1 = _norm180(azi1)
109 salp1, calp1 = _sincos2d(_around(azi1))
110 if name_:
111 self.name = name_
113 self._gX = gX # GeodesicExact only
114 self._lat1 = lat1 = _fix90(lat1)
115 self._lon1 = lon1
116 self._azi1 = azi1
117 self._salp1 = salp1
118 self._calp1 = calp1
119 # allow lat, azimuth and unrolling of lon
120 self._caps |= caps | gX.caps # | Caps._AZIMUTH_LATITUDE_LONG_UNROLL
122 self._toNAN = _toNAN(self._caps, lat1, lon1, azi1, salp1, calp1)
124 sbet1, cbet1 = _sinf1cos2d(_around(lat1), gX.f1)
125 self._dn1 = gX._dn(sbet1, cbet1)
126 # Evaluate alp0 from sin(alp1) * cos(bet1) = sin(alp0), with alp0
127 # in [0, pi/2 - |bet1|]. Alt: calp0 = hypot(sbet1, calp1 * cbet1),
128 # but the following is slightly better, consider the case salp1 = 0.
129 self._salp0, self._calp0 = _sin1cos2(salp1, calp1, sbet1, cbet1)
130 self._k2 = self._calp0**2 * gX.ep2
131 # Evaluate sig with tan(bet1) = tan(sig1) * cos(alp1).
132 # sig = 0 is nearest northward crossing of equator.
133 # With bet1 = 0, alp1 = pi/2, we have sig1 = 0 (equatorial line).
134 # With bet1 = pi/2, alp1 = -pi, sig1 = pi/2
135 # With bet1 = -pi/2, alp1 = 0 , sig1 = -pi/2
136 # Evaluate omg1 with tan(omg1) = sin(alp0) * tan(sig1).
137 # With alp0 in (0, pi/2], quadrants for sig and omg coincide.
138 # No atan2(0,0) ambiguity at poles since cbet1 = +epsilon.
139 # With alp0 = 0, omg1 = 0 for alp1 = 0, omg1 = pi for alp1 = pi.
140 self._somg1 = sbet1 * self._salp0
141 self._comg1 = c = (cbet1 * calp1) if (sbet1 or calp1) else _1_0
142 # Without normalization we have schi1 = somg1.
143 self._cchi1 = gX.f1 * self._dn1 * c
144 self._ssig1, self._csig1 = _norm2(sbet1, c) # sig1 in (-pi, pi]
145 # _norm2(somg1, comg1) # no need to normalize!
146 # _norm2(schi1?, cchi1) # no need to normalize!
147 if not (caps & Caps.LINE_OFF):
148 _glXs.append(self)
149 # no need to pre-compute other attrs for (caps & Caps.X). All are
150 # Property_RO's, computed once and cached/memoized until reset when
151 # arc, distance, C4order is changed or Elliptic function is reset.
153 def __del__(self): # XXX use weakref?
154 if _glXs: # may be empty or None
155 try: # PYCHOK no cover
156 _glXs.remove(self)
157 except (TypeError, ValueError):
158 pass
159 self._gX = None
160 # _update_all(self) # throws TypeError during Python 2 cleanup
162 def _update(self, updated, *attrs, **unused):
163 if updated:
164 _update_all(self, *attrs)
166 @Property_RO
167 def a1(self):
168 '''Get the I{equatorial arc} (C{degrees}), the arc length between
169 the northward equatorial crossing and the first point.
170 '''
171 return _atan2d(self._ssig1, self._csig1) # or NAN
173 equatorarc = a1
175 @Property_RO
176 def a13(self):
177 '''Get the arc length to reference point 3 (C{degrees}).
179 @see: Methods L{Arc} and L{SetArc}.
180 '''
181 return self._a13
183 def Arc(self):
184 '''Return the arc length to reference point 3 (C{degrees} or C{NAN}).
186 @see: Method L{SetArc} and property L{a13}.
187 '''
188 return self.a13
190 def ArcPosition(self, a12, outmask=Caps.STANDARD):
191 '''Find the position on the line given B{C{a12}}.
193 @arg a12: Spherical arc length from the first point to the
194 second point (C{degrees}).
195 @kwarg outmask: Bit-or'ed combination of L{Caps<pygeodesy.karney.Caps>}
196 values specifying the quantities to be returned.
198 @return: A L{GDict} with up to 12 items C{lat1, lon1, azi1, lat2,
199 lon2, azi2, m12, a12, s12, M12, M21, S12} with C{lat1},
200 C{lon1}, C{azi1} and arc length C{a12} always included,
201 except when C{a12=NAN}.
203 @note: By default, C{B{outmask}=STANDARD}, meaning thc C{lat1},
204 C{lon1}, C{azi1}, C{lat2}, C{lon2}, C{azi2}, C{s12} and
205 C{a12} entries are returned, except when C{a12=NAN}.
206 '''
207 return self._GDictPosition(True, a12, outmask)
209 @Property_RO
210 def azi0(self):
211 '''Get the I{equatorial azimuth}, the azimuth of this geodesic line
212 as it crosses the equator in a northward direction (C{degrees90}).
213 '''
214 return _atan2d(*self.azi0_sincos2) # or NAN
216 equatorazimuth = azi0
218 @Property_RO
219 def azi0_sincos2(self):
220 '''Get the sine and cosine of the I{equatorial azimuth} (2-tuple C{(sin, cos)}).
221 '''
222 return self._salp0, self._calp0
224 @Property_RO
225 def azi1(self):
226 '''Get the azimuth at the first point (compass C{degrees}).
227 '''
228 return self._azi1
230 @Property_RO
231 def azi1_sincos2(self):
232 '''Get the sine and cosine of the first point's azimuth (2-tuple C{(sin, cos)}).
233 '''
234 return self._salp1, self._calp1
236 @Property_RO
237 def _B41(self):
238 '''(INTERNAL) Cached/memoized.
239 '''
240 return _cosSeries(self._C4a, self._ssig1, self._csig1)
242 @Property_RO
243 def _C4a(self):
244 '''(INTERNAL) Cached/memoized.
245 '''
246 return self.geodesic._C4f_k2(self._k2)
248 @Property_RO
249 def _caps_DISTANCE_IN(self):
250 '''(INTERNAL) Get C{Caps.DISTANCE_IN} and C{_OUT}.
251 '''
252 return self.caps & (Caps.DISTANCE_IN & Caps._OUT_MASK)
254 @Property_RO
255 def _D0k2(self):
256 '''(INTERNAL) Cached/memoized.
257 '''
258 return self._eF.cD * _2__PI * self._k2
260 @Property_RO
261 def _D1(self):
262 '''(INTERNAL) Cached/memoized.
263 '''
264 return self._eF.deltaD(self._ssig1, self._csig1, self._dn1)
266 def Distance(self):
267 '''Return the distance to reference point 3 (C{meter} or C{NAN}).
269 @see: Method L{SetDistance} and property L{s13}.
270 '''
271 return self.s13
273 @Property_RO
274 def _E0b(self):
275 '''(INTERNAL) Cached/memoized.
276 '''
277 return self._eF.cE * _2__PI * self.geodesic.b
279 @Property_RO
280 def _E1(self):
281 '''(INTERNAL) Cached/memoized.
282 '''
283 return self._eF.deltaE(self._ssig1, self._csig1, self._dn1)
285 @Property_RO
286 def _eF(self):
287 '''(INTERNAL) Cached/memoized C{Elliptic} function.
288 '''
289 e = _MODS.elliptic
290 try: # see .gx.GeodesicExact._ef_reset_k2
291 return e.Elliptic(k2=-self._k2, alpha2=-self.geodesic.ep2)
292 except e.EllipticError: # nonfinite
293 return None
295 def _GDictPosition(self, arcmode, s12_a12, outmask=Caps.STANDARD): # MCCABE 17
296 '''(INTERNAL) Generate a new position along the geodesic.
298 @return: A L{GDict} with up to 12 items C{lat1, lon1, azi1, lat2,
299 lon2, azi2, m12, a12, s12, M12, M21, S12} with C{lat1},
300 C{lon1}, C{azi1} and arc length C{a12} always included,
301 except when C{a12=NAN}.
302 '''
303 r, Cs = GDict(), Caps
304 if outmask:
305 outmask &= self._caps & Cs._OUT_MASK
306 eF = self._eF
307 if eF is None or self._toNAN or not isfinite(s12_a12): # _toNAN(outmask, s12_a12)?
308 # E2 = sig12 = ssig12 = csig12 = NAN
309 d = dict(a12=s12_a12) if arcmode else dict(s12=s12_a12)
310 return r._toNAN(outmask | Cs.NONFINITONAN, # for backward compatibility
311 lat1=self.lat1, lon1=self.lon1, azi1=self.azi1, **d)
312 gX = self.geodesic # ._gX
314 if arcmode: # s12_a12 is (spherical) arc length
315 r.set_(a12=s12_a12, s12=NAN)
316 sig12 = radians(s12_a12)
317 ssig12, csig12 = sincos2(sig12) # utily, no NEG0
318 if not _K_2_0: # PYCHOK no cover
319 d = fremainder(fabs(s12_a12), _180_0)
320 if d == 90:
321 csig12 = _0_0
322 elif d == 0:
323 ssig12 = _0_0
324 E2 = _0_0
325 elif self._caps_DISTANCE_IN: # s12_a12 is distance
326 t = s12_a12 / self._E0b
327 s, c = _sincos2(t) # tau12
328 # tau2 = tau1 + tau12
329 E2 = -eF.deltaEinv(*_sincos12(-s, c, *self._stau1_ctau1))
330 sig12 = fsum1f_(self._E1, -E2, t) # == t - (E2 - E1)
331 ssig12, csig12 = _sincos2(sig12)
332 r.set_(a12=degrees(sig12), s12=s12_a12)
333 else: # uninitialized or impossible distance requested
334 return r.set_(a12=NAN, s12=NAN)
336 # sig2 = sig1 + sig12
337 ssig1, csig1 = self._ssig1, self._csig1
338 ssig2, csig2 = t = _sincos12(-ssig12, csig12, ssig1, csig1)
339 dn2 = eF.fDelta(*t)
341 if (outmask & Cs.DISTANCE):
342 if arcmode: # or f_0_01
343 E2 = eF.deltaE(ssig2, csig2, dn2)
344 # AB1 = _E0 * (E2 - _E1)
345 # s12 = _b * (_E0 * sig12 + AB1)
346 # = _b * _E0 * (sig12 + (E2 - _E1))
347 # = _b * _E0 * (E2 - _E1 + sig12)
348 s12 = self._E0b * fsum1f_(E2, -self._E1, sig12)
349 else:
350 s12 = s12_a12
351 r.set_(s12=s12)
353 if not (outmask ^ Cs.DISTANCE): # all done, see ._GenSet
354 return r
356 if self._debug: # PYCHOK no cover
357 outmask |= self._debug & Cs._DEBUG_DIRECT_LINE
359 if (outmask & Cs._DEBUG_DIRECT_LINE): # PYCHOK no cover
360 r.set_(sig12=sig12, dn2=dn2, b=gX.b, e2=gX.e2, f1=gX.f1,
361 E0b=self._E0b, E1=self._E1, E2=E2, eFk2=eF.k2, eFa2=eF.alpha2)
363 # sin(bet2) = cos(alp0) * sin(sig2) and
364 # cbet2 = hypot(salp0, calp0 * csig2). Alt:
365 # cbet2 = hypot(csig2, salp0 * ssig2)
366 salp0, calp0 = self._salp0, self._calp0
367 sbet2, cbet2 = _sin1cos2(calp0, salp0, csig2, ssig2)
368 if cbet2 == 0: # salp0 = 0, csig2 = 0, break degeneracy
369 cbet2 = csig2 = _TINY
370 # tan(alp0) = cos(sig2) * tan(alp2)
371 salp2 = salp0
372 calp2 = calp0 * csig2 # no need to normalize
374 if (outmask & Cs.AZIMUTH):
375 r.set_(azi2=_atan2d_reverse(salp2, calp2,
376 reverse=outmask & Cs.REVERSE2))
378 if (outmask & Cs.LATITUDE):
379 r.set_(lat2=_atan2d(sbet2, gX.f1 * cbet2))
381 if (outmask & Cs.LONGITUDE):
382 schi1 = self._somg1
383 cchi1 = self._cchi1
384 schi2 = ssig2 * salp0 # schi2 = somg2 without normalization
385 cchi2 = gX.f1 * dn2 * csig2
386 lam12 = salp0 * self._H0e2_f1 * fsum1f_(eF.deltaH(ssig2, csig2, dn2),
387 -self._H1, sig12)
388 if (outmask & Cs.LONG_UNROLL):
389 e = _copysign_1_0(salp0) # east-going?
390 tchi1 = e * schi1
391 tchi2 = e * schi2
392 chi12 = e * fsum1f_(atan2(ssig1, csig1), -atan2(ssig2, csig2),
393 atan2(tchi2, cchi2), -atan2(tchi1, cchi1), sig12)
394 lon2 = self.lon1 + degrees(chi12 - lam12)
395 if fabs(lon2) > _360_0: # XXX kludge
396 lon2 = _norm180(lon2)
397 else:
398 chi12 = atan2(*_sincos12(schi1, cchi1, schi2, cchi2))
399 lon2 = _norm180(self._lon1_norm180 + _norm180(degrees(chi12 - lam12)))
400 r.set_(lon2=lon2)
401 if (outmask & Cs._DEBUG_DIRECT_LINE): # PYCHOK no cover
402 r.set_(ssig2=ssig2, chi12=chi12, H0e2_f1=self._H0e2_f1,
403 csig2=csig2, lam12=lam12, H1=self._H1)
405 if (outmask & Cs._REDUCEDLENGTH_GEODESICSCALE):
406 dn1 = self._dn1
407 J12 = self._D0k2 * fsumf_(eF.deltaD(ssig2, csig2, dn2), -self._D1, sig12)
408 if (outmask & Cs._DEBUG_DIRECT_LINE): # PYCHOK no cover
409 r.set_(ssig1=ssig1, dn1=dn1, D0k2=self._D0k2,
410 csig1=csig1, dn2=dn2, D1=self._D1, J12=J12)
411 if (outmask & Cs.REDUCEDLENGTH):
412 # Add parens around (csig1 * ssig2) and (ssig1 * csig2) to
413 # ensure accurate cancellation in the case of coincident points.
414 r.set_(m12=gX.b * fsum1f_(dn2 * (csig1 * ssig2),
415 -dn1 * (ssig1 * csig2),
416 -J12 * (csig1 * csig2)))
417 if (outmask & Cs.GEODESICSCALE):
418 t = self._k2 * (ssig2 - ssig1) * (ssig2 + ssig1) / (dn2 + dn1)
419 r.set_(M12=csig12 + ssig1 * (t * ssig2 - csig2 * J12) / dn1,
420 M21=csig12 - ssig2 * (t * ssig1 - csig1 * J12) / dn2)
422 if (outmask & Cs.AREA):
423 A4 = salp0 * calp0
424 if A4:
425 # tan(alp) = tan(alp0) * sec(sig)
426 # tan(alp2-alp1) = (tan(alp2) - tan(alp1)) / (tan(alp2) * tan(alp1) + 1)
427 # = calp0 * salp0 * (csig1 - csig2) / (salp0^2 + calp0^2 * csig1 * csig2)
428 # If csig12 > 0, write
429 # csig1 - csig2 = ssig12 * (csig1 * ssig12 / (1 + csig12) + ssig1)
430 # else
431 # csig1 - csig2 = csig1 * (1 - csig12) + ssig12 * ssig1
432 # No need to normalize
433 salp12 = (((ssig12 * csig1 / (_1_0 + csig12) + ssig1) * ssig12) if csig12 > 0 else
434 (csig1 * (_1_0 - csig12) + ssig1 * ssig12)) * A4
435 calp12 = salp0**2 + calp0**2 * csig1 * csig2
436 A4 *= gX._e2a2
437 B41 = self._B41
438 B42 = _cosSeries(self._C4a, ssig2, csig2)
439 S12 = (B42 - B41) * A4
440 else:
441 S12 = A4 = B41 = B42 = _0_0
442 # alp12 = alp2 - alp1, used in atan2 so no need to normalize
443 salp12, calp12 = _sincos12(self._salp1, self._calp1, salp2, calp2)
444 # We used to include some patch up code that purported to deal
445 # with nearly meridional geodesics properly. However, this turned
446 # out to be wrong once salp1 = -0 was allowed (via InverseLine).
447 # In fact, the calculation of {s,c}alp12 was already correct
448 # (following the IEEE rules for handling signed zeros). So,
449 # the patch up code was unnecessary (as well as dangerous).
450 if (outmask & Cs._DEBUG_DIRECT_LINE): # PYCHOK no cover
451 r.set_(salp12=salp12, salp0=salp0, B41=B41, A4=A4,
452 calp12=calp12, calp0=calp0, B42=B42, c2=gX.c2)
453 S12 += gX.c2 * atan2(salp12, calp12)
454 r.set_(S12=S12)
456 r.set_(azi1=_norm180(self.azi1),
457 lat1=self.lat1, # == _fix90(lat1)
458 lon1=self.lon1 if (outmask & Cs.LONG_UNROLL) else self._lon1_norm180)
459 return r
461 def _GenPosition(self, arcmode, s12_a12, outmask):
462 '''(INTERNAL) Generate a new position along the geodesic.
464 @return: L{Direct9Tuple}C{(a12, lat2, lon2, azi2,
465 s12, m12, M12, M21, S12)}.
466 '''
467 r = self._GDictPosition(arcmode, s12_a12, outmask)
468 return r.toDirect9Tuple()
470 def _GenSet(self, debug, s12=None, a12=None, **llz2):
471 '''(INTERNAL) Aka C++ C{GenSetDistance}.
472 '''
473 Cs = Caps
474 if debug: # PYCHOK no cover
475 self._debug |= debug & Cs._DEBUG_ALL
476 # _CapsBase.debug._update(self)
477 if s12 is None:
478 if a12 is None: # see GeodesicExact.Line
479 return self
480 s12 = self._GDictPosition(True, a12, outmask=Cs.DISTANCE).s12 if a12 else _0_0
481 elif a12 is None:
482 a12 = self._GDictPosition(False, s12, 0).a12 if s12 else _0_0
483 self._s13 = s12
484 self._a13 = a12
485 self._caps |= Cs.DISTANCE | Cs.DISTANCE_IN
486 # _update_all(self) # new, from GeodesicExact.*Line
487 return _llz2gl(self, **llz2)
489 @Property_RO
490 def geodesic(self):
491 '''Get the I{exact} geodesic (L{GeodesicExact}).
492 '''
493 _xGeodesicExact(geodesic=self._gX)
494 return self._gX
496 def Intersecant2(self, lat0, lon0, radius, tol=_TOL):
497 '''Compute the intersection(s) of this geodesic line and a circle.
499 @arg lat0: Latitude of the circle center (C{degrees}).
500 @arg lon0: Longitude of the circle center (C{degrees}).
501 @arg radius: Radius of the circle (C{meter}, conventionally).
502 @kwarg tol: Convergence tolerance (C{scalar}).
504 @return: 2-Tuple C{(P, Q)} with both intersections (representing
505 a geodesic chord), each a L{GDict} from method L{Position}
506 extended to 14 items by C{lon0, lat0, azi0, a02, s02, at}
507 with the circle center C{lat0}, C{lon0}, azimuth C{azi0}
508 at, distance C{a02} in C{degrees} and C{s02} in C{meter}
509 along the geodesic from the circle center to the intersection
510 C{lat2}, C{lon2} and the angle C{at} between the geodesic
511 and this line at the intersection. The geodesic azimuth
512 at the intersection is C{(at + azi2)}. If this geodesic
513 line is tangential to the circle, both points are the same
514 L{GDict} instance.
516 @raise IntersectionError: The circle and this geodesic line do not
517 intersect, no I{perpencular} geodetic
518 intersection or no convergence.
520 @raise UnitError: Invalid B{C{radius}}.
521 '''
522 try:
523 return _MODS.geodesicw._Intersecant2(self, lat0, lon0, radius, tol=tol)
524 except (TypeError, ValueError) as x:
525 raise _xError(x, lat0, lon0, radius, tol=_TOL)
527 @Property_RO
528 def _H0e2_f1(self):
529 '''(INTERNAL) Cached/memoized.
530 '''
531 return self._eF.cH * _2__PI * self.geodesic._e2_f1
533 @Property_RO
534 def _H1(self):
535 '''(INTERNAL) Cached/memoized.
536 '''
537 return self._eF.deltaH(self._ssig1, self._csig1, self._dn1)
539 @Property_RO
540 def lat1(self):
541 '''Get the latitude of the first point (C{degrees}).
542 '''
543 return self._lat1
545 @Property_RO
546 def lon1(self):
547 '''Get the longitude of the first point (C{degrees}).
548 '''
549 return self._lon1
551 @Property_RO
552 def _lon1_norm180(self):
553 '''(INTERNAL) Cached/memoized.
554 '''
555 return _norm180(self._lon1)
557 def PlumbTo(self, lat0, lon0, est=None, tol=_TOL):
558 '''Compute the I{perpendicular} intersection of this geodesic line
559 and a geodesic from the given point.
561 @arg lat0: Latitude of the point (C{degrees}).
562 @arg lon0: Longitude of the point (C{degrees}).
563 @kwarg est: Optional, initial estimate for the distance C{s12} of
564 the intersection I{along} this geodesic line (C{meter}).
565 @kwarg tol: Convergence tolerance (C(meter)).
567 @return: The intersection point on this geodesic line, a L{GDict}
568 from method L{Position} extended to 14 items C{lat1, lon1,
569 azi1, lat2, lon2, azi2, a12, s12, lat0, lon0, azi0, a02,
570 s02, at} with distance C{a02} in C{degrees} and C{s02} in
571 C{meter} between the given C{lat0, lon0} point and the
572 intersection C{lat2, lon2}, azimuth C{azi0} at the given
573 point and C{at} the (perpendicular) angle between the
574 geodesic and this line at the intersection. The geodesic
575 azimuth at the intersection is C{(at + azi2)}. See method
576 L{Position} for further details.
578 @see: Methods C{Intersecant2}, C{Intersection} and C{Position}.
579 '''
580 return _MODS.geodesicw._PlumbTo(self, lat0, lon0, est=est, tol=tol)
582 def Position(self, s12, outmask=Caps.STANDARD):
583 '''Find the position on the line given B{C{s12}}.
585 @arg s12: Distance from this this line's first point (C{meter}).
586 @kwarg outmask: Bit-or'ed combination of L{Caps<pygeodesy.karney.Caps>}
587 values specifying the quantities to be returned.
589 @return: A L{GDict} with up to 12 items C{lat1, lon1, azi1, lat2,
590 lon2, azi2, m12, a12, s12, M12, M21, S12} with C{lat1},
591 C{lon1}, C{azi1} and arc length C{a12} always included,
592 except when C{a12=NAN}.
594 @note: By default, C{B{outmask}=STANDARD}, meaning thc C{lat1},
595 C{lon1}, C{azi1}, C{lat2}, C{lon2}, C{azi2}, C{s12} and
596 C{a12} entries are returned, except when C{a12=NAN}.
598 @note: This L{GeodesicLineExact} instance must have been
599 constructed with capability C{Caps.DISTANCE_IN} set.
600 '''
601 return self._GDictPosition(False, s12, outmask)
603 @Property_RO
604 def s13(self):
605 '''Get the distance to reference point 3 (C{meter} or C{NAN}).
607 @see: Methods L{Distance} and L{SetDistance}.
608 '''
609 return self._s13
611 def SetArc(self, a13):
612 '''Set reference point 3 in terms relative to the first point.
614 @arg a13: Spherical arc length from the first to the reference
615 point (C{degrees}).
617 @return: The distance C{s13} (C{meter}) between the first and
618 the reference point or C{NAN}.
619 '''
620 if self._a13 != a13:
621 self._GenSet(0, a12=a13)
622 _update_all(self)
623 return self._s13
625 def SetDistance(self, s13):
626 '''Set reference point 3 in terms relative to the first point.
628 @arg s13: Distance from the first to the reference point (C{meter}).
630 @return: The arc length C{a13} (C{degrees}) between the first
631 and the reference point or C{NAN}.
632 '''
633 if self._s13 != s13:
634 self._GenSet(0, s12=s13)
635 _update_all(self)
636 return self._a13
638 @Property_RO
639 def _stau1_ctau1(self):
640 '''(INTERNAL) Cached/memoized.
641 '''
642 s, c = _sincos2(self._E1)
643 # tau1 = sig1 + B11
644 return _sincos12(-s, c, self._ssig1, self._csig1)
645 # unnecessary because Einv inverts E
646 # return -self._eF.deltaEinv(stau1, ctau1)
648 @property_ROver
649 def _toProps7(self):
650 '''(INTERNAL) 7-Tuple of C{toStr} properties.
651 '''
652 C = _GeodesicLineExact
653 return C.lat1, C.lon1, C.azi1, C.a13, C.s13, C.caps, C.geodesic
655 def toStr(self, **prec_sep_name): # PYCHOK signature
656 '''Return this C{GeodesicLineExact} as string.
658 @see: L{Ellipsoid.toStr<pygeodesy.ellipsoids.Ellipsoid.toStr>}
659 for further details.
661 @return: C{GeodesicLineExact} (C{str}).
662 '''
663 return self._instr(props=self._toProps7, **prec_sep_name)
666__all__ += _ALL_DOCS(_GeodesicLineExact)
668# **) MIT License
669#
670# Copyright (C) 2016-2025 -- mrJean1 at Gmail -- All Rights Reserved.
671#
672# Permission is hereby granted, free of charge, to any person obtaining a
673# copy of this software and associated documentation files (the "Software"),
674# to deal in the Software without restriction, including without limitation
675# the rights to use, copy, modify, merge, publish, distribute, sublicense,
676# and/or sell copies of the Software, and to permit persons to whom the
677# Software is furnished to do so, subject to the following conditions:
678#
679# The above copyright notice and this permission notice shall be included
680# in all copies or substantial portions of the Software.
681#
682# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
683# OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
684# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
685# THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
686# OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
687# ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
688# OTHER DEALINGS IN THE SOFTWARE.