Coverage for pygeodesy/gars.py: 97%
143 statements
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« prev ^ index » next coverage.py v7.2.2, created at 2023-04-02 08:40 -0400
2# -*- coding: utf-8 -*-
4u'''I{Global Area Reference System} (GARS) en-/decoding.
6Classes L{Garef} and L{GARSError} and several functions to encode,
7decode and inspect I{Global Area Reference System} (GARS) references.
9Transcoded from C++ class U{GARS
10<https://GeographicLib.SourceForge.io/C++/doc/classGeographicLib_1_1GARS.html>}
11by I{Charles Karney}. See also U{Global Area Reference System
12<https://WikiPedia.org/wiki/Global_Area_Reference_System>} and U{NGA (GARS)
13<https://Earth-Info.NGA.mil/GandG/coordsys/grids/gars.html>}.
14'''
16# from pygeodesy.basics import isstr # from .dms
17from pygeodesy.constants import _off90, _1_over, _0_5, \
18 _1_0 # PYCHOK used!
19from pygeodesy.dms import Fmt, isstr, parse3llh # parseDMS2
20from pygeodesy.errors import _ValueError, _xkwds
21from pygeodesy.interns import NN, _0to9_, _AtoZnoIO_, _COMMA_
22from pygeodesy.lazily import _ALL_LAZY, _ALL_OTHER
23from pygeodesy.named import nameof, Property_RO
24from pygeodesy.namedTuples import LatLon2Tuple, LatLonPrec3Tuple
25# from pygeodesy.props import Property_RO # from .named
26# from pygeodesy.streprs import Fmt # from .dms
27from pygeodesy.units import Int_, Lat, Lon, Precision_, Scalar_, \
28 Str, _xStrError
30from math import floor
32__all__ = _ALL_LAZY.gars
33__version__ = '22.09.29'
35_Digits = _0to9_
36_LatLen = 2
37_LatOrig = -90
38_Letters = _AtoZnoIO_
39_LonLen = 3
40_LonOrig = -180
41_MaxPrec = 2
43_MinLen = _LonLen + _LatLen
44_MaxLen = _MinLen + _MaxPrec
46_M1 = _M2 = 2
47_M3 = 3
48_M4 = _M1 * _M2 * _M3
50_LatOrig_M4 = _LatOrig * _M4
51_LatOrig_M1 = _LatOrig * _M1
52_LonOrig_M4 = _LonOrig * _M4
53_LonOrig_M1_1 = _LonOrig * _M1 - 1
55_Resolutions = _1_over(_M1), _1_over(_M1 * _M2), _1_over(_M4)
58def _2divmod2(ll, _Orig_M4):
59 x = int(floor(ll * _M4)) - _Orig_M4
60 i = (x * _M1) // _M4
61 x -= i * _M4 // _M1
62 return i, x
65def _2fll(lat, lon, *unused):
66 '''(INTERNAL) Convert lat, lon.
67 '''
68 # lat, lon = parseDMS2(lat, lon)
69 return (Lat(lat, Error=GARSError),
70 Lon(lon, Error=GARSError))
73# def _2Garef(garef):
74# '''(INTERNAL) Check or create a L{Garef} instance.
75# '''
76# if not isinstance(garef, Garef):
77# try:
78# garef = Garef(garef)
79# except (TypeError, ValueError):
80# raise _xStrError(Garef, Str, garef=garef)
81# return garef
84def _2garstr2(garef):
85 '''(INTERNAL) Check a garef string.
86 '''
87 try:
88 n, garstr = len(garef), garef.upper()
89 if n < _MinLen or n > _MaxLen \
90 or garstr[:3] == 'INV' \
91 or not garstr.isalnum():
92 raise ValueError
93 return garstr, _2Precision(n - _MinLen)
95 except (AttributeError, TypeError, ValueError) as x:
96 raise GARSError(Garef.__name__, garef, cause=x)
99def _2Precision(precision):
100 '''(INTERNAL) Return a L{Precision_} instance.
101 '''
102 return Precision_(precision, Error=GARSError, low=0, high=_MaxPrec)
105class GARSError(_ValueError):
106 '''Global Area Reference System (GARS) encode, decode or other L{Garef} issue.
107 '''
108 pass
111class Garef(Str):
112 '''Garef class, a named C{str}.
113 '''
114 # no str.__init__ in Python 3
115 def __new__(cls, cll, precision=1, name=NN):
116 '''New L{Garef} from an other L{Garef} instance or garef
117 C{str} or from a C{LatLon} instance or lat-/longitude C{str}.
119 @arg cll: Cell or location (L{Garef} or C{str}, C{LatLon}
120 or C{str}).
121 @kwarg precision: Optional, the desired garef resolution
122 and length (C{int} 0..2), see function
123 L{gars.encode} for more details.
124 @kwarg name: Optional name (C{str}).
126 @return: New L{Garef}.
128 @raise RangeError: Invalid B{C{cll}} lat- or longitude.
130 @raise TypeError: Invalid B{C{cll}}.
132 @raise GARSError: INValid or non-alphanumeric B{C{cll}}.
133 '''
134 ll = p = None
136 if isinstance(cll, Garef):
137 g, p = _2garstr2(str(cll))
139 elif isstr(cll):
140 if _COMMA_ in cll:
141 ll = _2fll(*parse3llh(cll))
142 g = encode(*ll, precision=precision) # PYCHOK false
143 else:
144 g = cll.upper()
146 else: # assume LatLon
147 try:
148 ll = _2fll(cll.lat, cll.lon)
149 g = encode(*ll, precision=precision) # PYCHOK false
150 except AttributeError:
151 raise _xStrError(Garef, cll=cll) # Error=GARSError
153 self = Str.__new__(cls, g, name=name or nameof(cll))
154 self._latlon = ll
155 self._precision = p
156 return self
158 @Property_RO
159 def decoded3(self):
160 '''Get this garef's attributes (L{LatLonPrec3Tuple}).
161 '''
162 lat, lon = self.latlon
163 return LatLonPrec3Tuple(lat, lon, self.precision, name=self.name)
165 @Property_RO
166 def _decoded3(self):
167 '''(INTERNAL) Initial L{LatLonPrec5Tuple}.
168 '''
169 return decode3(self)
171 @Property_RO
172 def latlon(self):
173 '''Get this garef's (center) lat- and longitude (L{LatLon2Tuple}).
174 '''
175 lat, lon = self._latlon or self._decoded3[:2]
176 return LatLon2Tuple(lat, lon, name=self.name)
178 @Property_RO
179 def precision(self):
180 '''Get this garef's precision (C{int}).
181 '''
182 p = self._precision
183 return self._decoded3.precision if p is None else p
185 def toLatLon(self, LatLon, **LatLon_kwds):
186 '''Return (the center of) this garef cell as an instance
187 of the supplied C{LatLon} class.
189 @arg LatLon: Class to use (C{LatLon}).
190 @kwarg LatLon_kwds: Optional, additional B{C{LatLon}}
191 keyword arguments.
193 @return: This garef location (B{C{LatLon}}).
195 @raise GARSError: Invalid B{C{LatLon}}.
196 '''
197 if LatLon is None:
198 kwds = _xkwds(LatLon_kwds, LatLon=None, name=self.name)
199 raise GARSError(**kwds)
201 return self._xnamed(LatLon(*self.latlon, **LatLon_kwds))
204def decode3(garef, center=True):
205 '''Decode a C{garef} to lat-, longitude and precision.
207 @arg garef: To be decoded (L{Garef} or C{str}).
208 @kwarg center: If C{True} the center, otherwise the south-west,
209 lower-left corner (C{bool}).
211 @return: A L{LatLonPrec3Tuple}C{(lat, lon, precision)}.
213 @raise GARSError: Invalid B{C{garef}}, INValid, non-alphanumeric
214 or bad length B{C{garef}}.
215 '''
216 def _Error(i):
217 return GARSError(garef=Fmt.SQUARE(repr(garef), i))
219 def _ll(chars, g, i, j, lo, hi):
220 ll, b = 0, len(chars)
221 for i in range(i, j):
222 d = chars.find(g[i])
223 if d < 0:
224 raise _Error(i)
225 ll = ll * b + d
226 if ll < lo or ll > hi:
227 raise _Error(j)
228 return ll
230 def _ll2(lon, lat, g, i, m):
231 d = _Digits.find(g[i])
232 if d < 1 or d > m * m:
233 raise _Error(i)
234 d, r = divmod(d - 1, m)
235 lon = lon * m + r
236 lat = lat * m + (m - 1 - d)
237 return lon, lat
239 g, precision = _2garstr2(garef)
241 lon = _ll(_Digits, g, 0, _LonLen, 1, 720) + _LonOrig_M1_1
242 lat = _ll(_Letters, g, _LonLen, _MinLen, 0, 359) + _LatOrig_M1
243 if precision > 0:
244 lon, lat = _ll2(lon, lat, g, _MinLen, _M2)
245 if precision > 1:
246 lon, lat = _ll2(lon, lat, g, _MinLen + 1, _M3)
248 if center: # ll = (ll * 2 + 1) / 2
249 lon += _0_5
250 lat += _0_5
252 r = _Resolutions[precision] # == 1.0 / unit
253 return LatLonPrec3Tuple(Lat(lat * r, Error=GARSError),
254 Lon(lon * r, Error=GARSError),
255 precision, name=nameof(garef))
258def encode(lat, lon, precision=1): # MCCABE 14
259 '''Encode a lat-/longitude as a C{garef} of the given precision.
261 @arg lat: Latitude (C{degrees}).
262 @arg lon: Longitude (C{degrees}).
263 @kwarg precision: Optional, the desired C{garef} resolution
264 and length (C{int} 0..2).
266 @return: The C{garef} (C{str}).
268 @raise RangeError: Invalid B{C{lat}} or B{C{lon}}.
270 @raise GARSError: Invalid B{C{precision}}.
272 @note: The C{garef} length is M{precision + 5} and the C{garef}
273 resolution is B{30′} for B{C{precision}} 0, B{15′} for 1
274 and B{5′} for 2, respectively.
275 '''
276 def _digit(x, y, m):
277 return _Digits[m * (m - y - 1) + x + 1],
279 def _str(chars, x, n):
280 s, b = [], len(chars)
281 for i in range(n):
282 x, i = divmod(x, b)
283 s.append(chars[i])
284 return tuple(reversed(s))
286 p = _2Precision(precision)
288 lat, lon = _2fll(lat, lon)
289 lat = _off90(lat)
291 ix, x = _2divmod2(lon, _LonOrig_M4)
292 iy, y = _2divmod2(lat, _LatOrig_M4)
294 g = _str(_Digits, ix + 1, _LonLen) + _str(_Letters, iy, _LatLen)
295 if p > 0:
296 ix, x = divmod(x, _M3)
297 iy, y = divmod(y, _M3)
298 g += _digit(ix, iy, _M2)
299 if p > 1:
300 g += _digit(x, y, _M3)
302 return NN.join(g)
305def precision(res):
306 '''Determine the L{Garef} precision to meet a required (geographic)
307 resolution.
309 @arg res: The required resolution (C{degrees}).
311 @return: The L{Garef} precision (C{int} 0..2).
313 @raise ValueError: Invalid B{C{res}}.
315 @see: Function L{gars.encode} for more C{precision} details.
316 '''
317 r = Scalar_(res=res)
318 for p in range(_MaxPrec):
319 if resolution(p) <= r:
320 return p
321 return _MaxPrec
324def resolution(prec):
325 '''Determine the (geographic) resolution of a given L{Garef} precision.
327 @arg prec: The given precision (C{int}).
329 @return: The (geographic) resolution (C{degrees}).
331 @raise GARSError: Invalid B{C{prec}}.
333 @see: Function L{gars.encode} for more C{precision} details.
334 '''
335 p = Int_(prec=prec, Error=GARSError, low=-1, high=_MaxPrec + 1)
336 return _Resolutions[max(0, min(p, _MaxPrec))]
339__all__ += _ALL_OTHER(decode3, # functions
340 encode, precision, resolution)
342# **) MIT License
343#
344# Copyright (C) 2016-2023 -- mrJean1 at Gmail -- All Rights Reserved.
345#
346# Permission is hereby granted, free of charge, to any person obtaining a
347# copy of this software and associated documentation files (the "Software"),
348# to deal in the Software without restriction, including without limitation
349# the rights to use, copy, modify, merge, publish, distribute, sublicense,
350# and/or sell copies of the Software, and to permit persons to whom the
351# Software is furnished to do so, subject to the following conditions:
352#
353# The above copyright notice and this permission notice shall be included
354# in all copies or substantial portions of the Software.
355#
356# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
357# OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
358# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
359# THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
360# OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
361# ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
362# OTHER DEALINGS IN THE SOFTWARE.