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# -*- coding: utf-8 -*- 

 

u'''Classes L{Georef} and L{WGRSError} and several functions to encode, 

decode and inspect I{World Geographic Reference System (WGRS)} references. 

 

Transcribed from C++ class U{Georef 

<https://GeographicLib.SourceForge.io/html/classGeographicLib_1_1Georef.html>} 

by I{Charles Karney}, but with modified C{precision} and extended with 

C{height} and C{radius}. See also U{World Geographic Reference System 

<https://WikiPedia.org/wiki/World_Geographic_Reference_System>}. 

 

@newfield example: Example, Examples 

''' 

 

from pygeodesy.dms import parse3llh, parseDMS2 

from pygeodesy.fmath import EPS1_2, _IsNotError 

from pygeodesy.lazily import _ALL_LAZY 

from pygeodesy.named import LatLon2Tuple, LatLonPrec3Tuple, \ 

LatLonPrec5Tuple, _NamedStr 

from pygeodesy.utily import _MISSING, ft2m, m2ft, m2NM, property_RO, \ 

_Strs 

 

# all public contants, classes and functions 

__all__ = _ALL_LAZY.wgrs + ('decode3', 'decode5', # functions 

'encode', 'precision', 'resolution') 

__version__ = '20.01.22' 

 

_Base = 10 

_BaseLen = 4 

_Degrees = 'ABCDEFGHJKLMNPQ' 

_Digits = '0123456789' 

_LatOrig = -90 

_LatTile = 'ABCDEFGHJKLM' 

_LonOrig = -180 

_LonTile = 'ABCDEFGHJKLMNPQRSTUVWXYZ' 

_M = 60000000000 # = 60_000_000_000 = 60 * pow(10, 9) 

_MaxPrec = 11 

_Tile = 15 # tile size in degrees 

 

_MaxLen = _BaseLen + 2 * _MaxPrec 

_MinLen = _BaseLen - 2 

 

_LatOrig_M = _LatOrig * _M 

_LonOrig_M = _LonOrig * _M 

 

_LatOrig_Tile = float(_LatOrig) / _Tile 

_LonOrig_Tile = float(_LonOrig) / _Tile 

 

 

def _2divmod3(x, Orig_M): 

x *= _M 

i = int(x) 

if i > x: # floor(x * _M) 

i -= 1 

i, x = divmod(i - Orig_M, _M) 

xt, xd = divmod(i, _Tile) 

return xt, xd, x 

 

 

def _2fllh(lat, lon, height=None): 

'''(INTERNAL) Convert lat, lon, height. 

''' 

return parseDMS2(lat, lon) + (height,) 

 

 

def _2Georef(georef): 

'''(INTERNAL) Check or create a L{Georef} instance. 

''' 

if not isinstance(georef, Georef): 

try: 

georef = Georef(georef) 

except (TypeError, ValueError): 

raise _IsNotError(Georef.__name__, str.__name__, 'LatLon', georef=georef) 

return georef 

 

 

def _2geostr2(georef): 

'''(INTERNAL) Check a georef string. 

''' 

try: 

n, geostr = len(georef), georef.upper() 

p, o = divmod(n, 2) 

if o or n < _MinLen or n > _MaxLen \ 

or geostr[:3] == 'INV' \ 

or not geostr.isalnum(): 

raise ValueError 

except (AttributeError, TypeError, ValueError): 

raise WGRSError('%s: %r[%s]' % (Georef.__name__, georef, len(georef))) 

return geostr, p - 1 

 

 

class WGRSError(ValueError): 

'''World Geographic Reference System (WGRS) encode, decode or other L{Georef} issue. 

''' 

pass 

 

 

class Georef(_NamedStr): 

'''Georef class, a C{_NamedStr}. 

''' 

_height = _MISSING # meter 

_latlon = None # cached latlon property 

_precision = None 

_radius = _MISSING # meter 

 

# no str.__init__ in Python 3 

def __new__(cls, cll, precision=3, name=''): 

'''New L{Georef} from an other L{Georef} instance or georef 

C{str} or from a C{LatLon} instance or lat-/longitude C{str}. 

 

@param cll: Cell or location (L{Georef} or C{str}, C{LatLon} 

or C{str}). 

@keyword precision: Optional, the desired georef resolution 

and length (C{int} 0..11), see function 

L{wgrs.encode} for more details. 

@keyword name: Optional name (C{str}). 

 

@return: New L{Georef}. 

 

@raise RangeError: Invalid B{C{cll}} lat- or longitude. 

 

@raise TypeError: Invalid B{C{cll}}. 

 

@raise WGRSError: INValid or non-alphanumeric B{C{cll}}. 

''' 

if isinstance(cll, Georef): 

g, p = _2geostr2(str(cll)) 

self = str.__new__(cls, g) 

self._latlon = LatLon2Tuple(*cll._latlon) 

self._name = cll._name 

self._precision = p # cll._precision 

 

elif isinstance(cll, _Strs): 

if ',' in cll: 

lat, lon, h = _2fllh(*parse3llh(cll, height=None)) 

g = encode(lat, lon, precision=precision, height=h) # PYCHOK false 

self = str.__new__(cls, g) 

self._latlon = LatLon2Tuple(lat, lon) 

self._precision = precision 

if h not in (None, _MISSING): 

self._height = h 

else: 

self = str.__new__(cls, cll.upper()) 

self._decode() 

 

else: # assume LatLon 

try: 

lat, lon, h = _2fllh(cll.lat, cll.lon) 

h = getattr(cll, 'height', h) 

except AttributeError: 

raise _IsNotError('valid', **{Georef.__name__: cll}) 

g = encode(lat, lon, precision=precision, height=h) # PYCHOK false 

self = str.__new__(cls, g) 

self._latlon = LatLon2Tuple(lat, lon) 

self._precision = precision 

if h not in (None, _MISSING): 

self._height = h 

 

if name: 

self.name = name 

return self 

 

def _decode(self): 

# cache all decoded attrs 

lat, lon, p, h, r = decode5(self) # PYCHOK LatLonPrec5Tuple 

if self._latlon is None: 

self._latlon = LatLon2Tuple(lat, lon) 

if self._precision is None: 

self._precision = p 

if self._height is _MISSING: 

self._height = h 

if self._radius is _MISSING: 

self._radius = r 

 

@property_RO 

def height(self): 

'''Get this georef's height in C{meter} or C{None} if missing. 

''' 

if self._height is _MISSING: 

self._decode() 

return self._height 

 

@property_RO 

def latlon(self): 

'''Get this georef's (center) lat- and longitude (L{LatLon2Tuple}). 

''' 

if self._latlon is None: 

self._decode() 

return self._latlon 

 

@property_RO 

def precision(self): 

'''Get this georef's precision (C{int}). 

''' 

if self._precision is None: 

self._decode() 

return self._precision 

 

@property_RO 

def radius(self): 

'''Get this georef's radius in C{meter} or C{None} if missing. 

''' 

if self._radius is _MISSING: 

self._decode() 

return self._radius 

 

def toLatLon(self, LatLon, height=None, **kwds): 

'''Return (the center of) this georef cell as an instance 

of the supplied C{LatLon} class. 

 

@param LatLon: Class to use (C{LatLon}). 

@keyword height: Optional height ({meter}). 

@keyword kwds: Optional keyword arguments for B{C{LatLon}}. 

 

@return: This georef location (B{C{LatLon}}). 

 

@raise WGRSError: Invalid B{C{LatLon}}. 

''' 

if LatLon is None: 

raise WGRSError('%s invalid: %r' % ('LatLon', LatLon)) 

 

h = height if height is not None else (self.height or 0) 

return self._xnamed(LatLon(*self.latlon, height=h, **kwds)) 

 

 

def decode3(georef, center=True): 

'''Decode a C{georef} to lat-, longitude and precision. 

 

@param georef: To be decoded (L{Georef} or C{str}). 

@keyword center: If C{True} the center, otherwise the south-west, 

lower-left corner (C{bool}). 

 

@return: A L{LatLonPrec3Tuple}C{(lat, lon, precision)}. 

 

@raise WGRSError: Invalid B{C{georef}}, INValid, non-alphanumeric 

or odd length B{C{georef}}. 

''' 

def _digit(ll, g, i, m): 

d = _Digits.find(g[i]) 

if d < 0 or d >= m: 

raise _Error(i) 

return ll * m + d 

 

def _Error(i): 

return WGRSError('%s invalid: %r[%s]' % ('georef', georef, i)) 

 

def _index(chars, g, i): 

k = chars.find(g[i]) 

if k < 0: 

raise _Error(i) 

return k 

 

g, precision = _2geostr2(georef) 

lon = _index(_LonTile, g, 0) + _LonOrig_Tile 

lat = _index(_LatTile, g, 1) + _LatOrig_Tile 

 

u, p = 1.0, precision - 1 

if p >= 0: 

lon = lon * _Tile + _index(_Degrees, g, 2) 

lat = lat * _Tile + _index(_Degrees, g, 3) 

if p > 0: 

m = 6 

for i in range(p): 

lon = _digit(lon, g, _BaseLen + i, m) 

lat = _digit(lat, g, _BaseLen + i + p, m) 

u *= m 

m = _Base 

u *= _Tile 

 

if center: 

lon = lon * 2 + 1 

lat = lat * 2 + 1 

u *= 2 

u = _Tile / u 

lon *= u 

lat *= u 

return LatLonPrec3Tuple(lat, lon, precision) 

 

 

def decode5(georef, center=True): 

'''Decode a C{georef} to lat-, longitude, precision, height and radius. 

 

@param georef: To be decoded (L{Georef} or C{str}). 

@keyword center: If C{True} the center, otherwise the south-west, 

lower-left corner (C{bool}). 

 

@return: A L{LatLonPrec5Tuple}C{(lat, lon, 

precision, height, radius)} where C{height} and/or 

C{radius} are C{None} if missing. 

 

@raise WGRSError: Invalid B{C{georef}}, INValid, non-alphanumeric 

or odd length B{C{georef}}. 

''' 

def _h2m(kft): 

return ft2m(kft * 1000.0) 

 

def _r2m(NM): 

return NM / m2NM(1) 

 

def _split2(g, name, _2m): 

i = max(g.rfind(name[0].upper()), g.rfind(name[0])) 

if i > _BaseLen: 

try: 

return g[:i], _2m(int(g[i+1:])) 

except (IndexError, ValueError): 

raise WGRSError('%s invalid: %r' % (name, georef)) 

return g, None 

 

try: 

g = str(georef) 

except (TypeError, ValueError): 

raise WGRSError('%s invalid: %r' % ('georef', georef)) 

 

g, h = _split2(g, 'height', _h2m) # H is last 

g, r = _split2(g, 'radius', _r2m) # R before H 

 

a, b, p = decode3(g, center=center) 

return LatLonPrec5Tuple(a, b, p, h, r) 

 

 

def encode(lat, lon, precision=3, height=None, radius=None): # MCCABE 14 

'''Encode a lat-/longitude as a C{georef} of the given precision. 

 

@param lat: Latitude (C{degrees}). 

@param lon: Longitude (C{degrees}). 

@keyword precision: Optional, the desired C{georef} resolution 

and length (C{int} 0..11). 

@keyword height: Optional, height in C{meter}, see U{Designation of area 

<https://WikiPedia.org/wiki/World_Geographic_Reference_System>}. 

@keyword radius: Optional, radius in C{meter}, see U{Designation of area 

<https://WikiPedia.org/wiki/World_Geographic_Reference_System>}. 

 

@return: The C{georef} (C{str}). 

 

@raise RangeError: Invalid B{C{lat}} or B{C{lon}}. 

 

@raise WGRSError: Invalid B{C{precision}}, B{C{height}} or B{C{radius}}. 

 

@note: The B{C{precision}} value differs from U{Georef<https:// 

GeographicLib.SourceForge.io/html/classGeographicLib_1_1Georef.html>}. 

The C{georef} length is M{2 * (precision + 1)} and the 

C{georef} resolution is I{15°} for B{C{precision}} 0, I{1°} 

for 1, I{1′} for 2, I{0.1′} for 3, I{0.01′} for 4, ... 

M{10**(2 - precision)}. 

''' 

def _option(name, m, m2_, K): 

try: 

f = m2_(float(m) * K) 

if f < 0: 

raise ValueError 

except (TypeError, ValueError): 

raise WGRSError('%s invalid: %r' % (name, m)) 

return '%s%d' % (name[0].upper(), int(f + 0.5)) 

 

def _pstr(p, x): 

return '%0*d' % (p, x) 

 

try: 

p = int(precision) 

if p < 0 or p > _MaxPrec: 

raise ValueError 

except (TypeError, ValueError): 

raise WGRSError('%s invalid: %r' % ('precision', precision)) 

 

lat, lon, _ = _2fllh(lat, lon) 

if lat == 90: 

lat *= EPS1_2 

 

xt, xd, x = _2divmod3(lon, _LonOrig_M) 

yt, yd, y = _2divmod3(lat, _LatOrig_M) 

 

g = _LonTile[xt], _LatTile[yt] 

if p > 0: 

g += _Degrees[xd], _Degrees[yd] 

p -= 1 

if p > 0: 

d = pow(_Base, _MaxPrec - p) 

x = _pstr(p, x // d) 

y = _pstr(p, y // d) 

g += x, y 

 

if radius is not None: # R before H 

g += _option('radius', radius, m2NM, 1.0), 

if height is not None: # H is last 

g += _option('height', height, m2ft, 1e-3), 

 

return ''.join(g) 

 

 

def precision(res): 

'''Determine the L{Georef} precision to meet a required (geographic) 

resolution. 

 

@param res: The required resolution (C{degrees}). 

 

@return: The L{Georef} precision (C{int} 0..11). 

 

@see: Function L{wgrs.encode} for more C{precision} details. 

''' 

r = abs(res) 

for p in range(_MaxPrec): 

if resolution(p) <= r: 

return p 

return _MaxPrec 

 

 

def resolution(prec): 

'''Determine the (geographic) resolution of a given L{Georef} precision. 

 

@param prec: The given precision (C{int}). 

 

@return: The (geographic) resolution (C{degrees}). 

 

@see: Function L{wgrs.encode} for more C{precision} details. 

''' 

if prec < 1: 

r = float(_Tile) 

elif prec == 1: 

r = 1.0 

else: 

r = 1.0 / (60.0 * pow(_Base, min(prec, _MaxPrec) - 1)) 

return r 

 

# **) MIT License 

# 

# Copyright (C) 2016-2020 -- mrJean1 at Gmail -- All Rights Reserved. 

# 

# Permission is hereby granted, free of charge, to any person obtaining a 

# copy of this software and associated documentation files (the "Software"), 

# to deal in the Software without restriction, including without limitation 

# the rights to use, copy, modify, merge, publish, distribute, sublicense, 

# and/or sell copies of the Software, and to permit persons to whom the 

# Software is furnished to do so, subject to the following conditions: 

# 

# The above copyright notice and this permission notice shall be included 

# in all copies or substantial portions of the Software. 

# 

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS 

# OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 

# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 

# THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR 

# OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, 

# ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR 

# OTHER DEALINGS IN THE SOFTWARE.