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# -*- coding: utf-8 -*- 

 

u'''Geohash en-/decoding. 

 

Classes L{Geohash} and L{GeohashError} and several functions to 

encode, decode and inspect I{geohashes}. 

 

Transcoded from JavaScript originals by I{(C) Chris Veness 2011-2015} 

and published under the same MIT Licence**, see U{Geohashes 

<https://www.Movable-Type.co.UK/scripts/geohash.html>}. 

 

See also U{Geohash<https://WikiPedia.org/wiki/Geohash>}, 

U{Geohash<https://GitHub.com/vinsci/geohash>}, 

U{PyGeohash<https://PyPI.org/project/pygeohash>} and 

U{Geohash-Javascript<https://GitHub.com/DaveTroy/geohash-js>}. 

''' 

 

from pygeodesy.basics import isodd, isstr, map2 

from pygeodesy.dms import parse3llh # parseDMS2 

from pygeodesy.errors import _ValueError, _xkwds 

from pygeodesy.fmath import favg 

from pygeodesy.formy import equirectangular_ as _equirectangular_, \ 

equirectangular, euclidean, haversine, vincentys 

from pygeodesy.interns import EPS, NN, R_M, _COMMA_, _DOT_, _E_, \ 

_floatuple, _N_, _NE_, _NW_, _S_, _SE_, \ 

_SW_, _W_, _0_0, _0_5, _180_0, _360_0 

from pygeodesy.interns import _90_0 # PYCHOK used! 

from pygeodesy.lazily import _ALL_LAZY, _ALL_OTHER 

from pygeodesy.named import _NamedDict, _NamedTuple, nameof, _xnamed 

from pygeodesy.namedTuples import Bounds2Tuple, Bounds4Tuple, \ 

LatLon2Tuple, PhiLam2Tuple 

from pygeodesy.props import deprecated_function, deprecated_method, \ 

deprecated_property_RO, Property_RO 

from pygeodesy.streprs import fstr 

from pygeodesy.units import Degrees_, Int, Lat, Lon, Precision_, Str, \ 

_xStrError 

 

from math import ldexp, log10, radians 

 

__all__ = _ALL_LAZY.geohash 

__version__ = '21.06.23' 

 

 

class _GH(object): 

'''(INTERNAL) Lazily defined constants. 

''' 

def _4d(self, n, e, s, w): # helper 

return dict(N=(n, e), S=(s, w), 

E=(e, n), W=(w, s)) 

 

@Property_RO 

def Borders(self): 

return self._4d('prxz', 'bcfguvyz', '028b', '0145hjnp') 

 

Bounds4 = (-_90_0, -_180_0, _90_0, _180_0) 

 

@Property_RO 

def DecodedBase32(self): # inverse GeohashBase32 map 

return dict((c, i) for i, c in enumerate(self.GeohashBase32)) 

 

# Geohash-specific base32 map 

GeohashBase32 = '0123456789bcdefghjkmnpqrstuvwxyz' # no a, i, j and o 

 

@Property_RO 

def Neighbors(self): 

return self._4d('p0r21436x8zb9dcf5h7kjnmqesgutwvy', 

'bc01fg45238967deuvhjyznpkmstqrwx', 

'14365h7k9dcfesgujnmqp0r2twvyx8zb', 

'238967debc01fg45kmstqrwxuvhjyznp') 

 

@Property_RO 

def Sizes(self): # lat-, lon and radial size (in meter) 

# ... where radial = sqrt(latSize * lonWidth / PI) 

return (_floatuple(20032e3, 20000e3, 11292815.096), # 0 

_floatuple( 5003e3, 5000e3, 2821794.075), # 1 

_floatuple( 650e3, 1225e3, 503442.397), # 2 

_floatuple( 156e3, 156e3, 88013.575), # 3 

_floatuple( 19500, 39100, 15578.683), # 4 

_floatuple( 4890, 4890, 2758.887), # 5 

_floatuple( 610, 1220, 486.710), # 6 

_floatuple( 153, 153, 86.321), # 7 

_floatuple( 19.1, 38.2, 15.239), # 8 

_floatuple( 4.77, 4.77, 2.691), # 9 

_floatuple( 0.596, 1.19, 0.475), # 10 

_floatuple( 0.149, 0.149, 0.084), # 11 

_floatuple( 0.0186, 0.0372, 0.015)) # 12 _MaxPrec 

 

_GH = _GH() # PYCHOK singleton 

_MaxPrec = 12 

 

 

def _2bounds(LatLon, LatLon_kwds, s, w, n, e, name=NN): 

'''(INTERNAL) Return SW and NE bounds. 

''' 

if LatLon is None: 

r = Bounds4Tuple(s, w, n, e, name=name) 

else: 

sw = _xnamed(LatLon(s, w, **LatLon_kwds), name) 

ne = _xnamed(LatLon(n, e, **LatLon_kwds), name) 

r = Bounds2Tuple(sw, ne, name=name) 

return r # _xnamed(r, name) 

 

 

def _2center(bounds): 

'''(INTERNAL) Return the C{bounds} center. 

''' 

return (favg(bounds.latN, bounds.latS), 

favg(bounds.lonE, bounds.lonW)) 

 

 

def _2fll(lat, lon, *unused): 

'''(INTERNAL) Convert lat, lon to 2-tuple of floats. 

''' 

# lat, lon = parseDMS2(lat, lon) 

return (Lat(lat, Error=GeohashError), 

Lon(lon, Error=GeohashError)) 

 

 

def _2Geohash(geohash): 

'''(INTERNAL) Check or create a Geohash instance. 

''' 

return geohash if isinstance(geohash, Geohash) else \ 

Geohash(geohash) 

 

 

def _2geostr(geohash): 

'''(INTERNAL) Check a geohash string. 

''' 

try: 

if not (0 < len(geohash) <= _MaxPrec): 

raise ValueError 

geostr = geohash.lower() 

for c in geostr: 

if c not in _GH.DecodedBase32: 

raise ValueError 

return geostr 

except (AttributeError, TypeError, ValueError) as x: 

raise GeohashError(Geohash.__name__, geohash, txt=str(x)) 

 

 

class Geohash(Str): 

'''Geohash class, a named C{str}. 

''' 

# no str.__init__ in Python 3 

def __new__(cls, cll, precision=None, name=NN): 

'''New L{Geohash} from an other L{Geohash} instance or C{str} 

or from a C{LatLon} instance or C{str}. 

 

@arg cll: Cell or location (L{Geohash}, C{LatLon} or C{str}). 

@kwarg precision: Optional, the desired geohash length (C{int} 

1..12), see function L{geohash.encode} for 

some examples. 

@kwarg name: Optional name (C{str}). 

 

@return: New L{Geohash}. 

 

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

 

@raise TypeError: Invalid B{C{cll}}. 

''' 

ll = None 

 

if isinstance(cll, Geohash): 

gh = _2geostr(str(cll)) 

 

elif isstr(cll): 

if _COMMA_ in cll: 

ll = _2fll(*parse3llh(cll)) 

gh = encode(*ll, precision=precision) 

else: 

gh = _2geostr(cll) 

 

else: # assume LatLon 

try: 

ll = _2fll(cll.lat, cll.lon) 

gh = encode(*ll, precision=precision) 

except AttributeError: 

raise _xStrError(Geohash, cll=cll, Error=GeohashError) 

 

self = Str.__new__(cls, gh, name=name or nameof(cll)) 

self._latlon = ll 

return self 

 

@deprecated_property_RO 

def ab(self): 

'''DEPRECATED, use property C{philam}.''' 

return self.philam 

 

def adjacent(self, direction, name=NN): 

'''Determine the adjacent cell in given compass direction. 

 

@arg direction: Compass direction ('N', 'S', 'E' or 'W'). 

@kwarg name: Optional name (C{str}), otherwise the name 

of this cell plus C{.D}irection. 

 

@return: Geohash of adjacent cell (L{Geohash}). 

 

@raise GeohashError: Invalid geohash or B{C{direction}}. 

''' 

# based on <https://GitHub.com/DaveTroy/geohash-js> 

 

D = direction[:1].upper() 

if D not in _GH.Neighbors: 

raise GeohashError(direction=direction) 

 

e = 1 if isodd(len(self)) else 0 

 

c = self[-1:] # last hash char 

i = _GH.Neighbors[D][e].find(c) 

if i < 0: 

raise GeohashError(geohash=self) 

 

p = self[:-1] # hash without last char 

# check for edge-cases which don't share common prefix 

if p and (c in _GH.Borders[D][e]): 

p = Geohash(p).adjacent(D) 

 

n = name or self.name 

if n: 

n = _DOT_(n, D) 

# append letter for direction to parent 

return Geohash(p + _GH.GeohashBase32[i], name=n) 

 

@Property_RO 

def _bounds(self): 

'''(INTERNAL) Cache for L{bounds}. 

''' 

return bounds(self) 

 

def bounds(self, LatLon=None, **LatLon_kwds): 

'''Return the lower-left SW and upper-right NE bounds of this 

geohash cell. 

 

@kwarg LatLon: Optional class to return I{bounds} (C{LatLon}) 

or C{None}. 

@kwarg LatLon_kwds: Optional keyword arguments for B{C{LatLon}}, 

ignored if B{C{LatLon}} is C{None}. 

 

@return: A L{Bounds2Tuple}C{(latlonSW, latlonNE)} of B{C{LatLon}}s 

or a L{Bounds4Tuple}C{(latS, lonW, latN, lonE)} if 

C{B{LatLon}=None}, 

''' 

r = self._bounds 

return r if LatLon is None else \ 

_2bounds(LatLon, LatLon_kwds, *r, name=self.name) 

 

def _distanceTo(self, func_, other, **kwds): 

'''(INTERNAL) Helper for distances, see C{formy._distanceTo*}. 

''' 

lls = self.latlon + _2Geohash(other).latlon 

return func_(*lls, **kwds) 

 

def distanceTo(self, other): 

'''Estimate the distance between this and an other geohash 

based the cell sizes. 

 

@arg other: The other geohash (L{Geohash}, C{LatLon} or C{str}). 

 

@return: Approximate distance (C{meter}). 

 

@raise TypeError: The B{C{other}} is not a L{Geohash}, 

C{LatLon} or C{str}. 

''' 

other = _2Geohash(other) 

 

n = min(len(self), len(other), len(_GH.Sizes)) 

if n: 

for n in range(n): 

if self[n] != other[n]: 

break 

return _GH.Sizes[n][2] 

 

@deprecated_method 

def distance1To(self, other): # PYCHOK no cover 

'''DEPRECATED, use method L{distanceTo}.''' 

return self.distanceTo(other) 

 

distance1 = distance1To 

 

@deprecated_method 

def distance2To(self, other, radius=R_M, adjust=False, wrap=False): # PYCHOK no cover 

'''DEPRECATED, use method L{equirectangularTo}.''' 

return self.equirectangularTo(other, radius=radius, adjust=adjust, wrap=wrap) 

 

distance2 = distance2To 

 

@deprecated_method 

def distance3To(self, other, radius=R_M, wrap=False): # PYCHOK no cover 

'''DEPRECATED, use method L{haversineTo}.''' 

return self.haversineTo(other, radius=radius, wrap=wrap) 

 

distance3 = distance3To 

 

def equirectangularTo(self, other, radius=R_M, adjust=False, wrap=False): 

'''Approximate the distance between this and an other geohash 

using the L{equirectangular} function. 

 

@arg other: The other geohash (L{Geohash}, C{LatLon} or C{str}). 

@kwarg radius: Mean earth radius, ellipsoid or datum 

(C{meter}, L{Ellipsoid}, L{Ellipsoid2}, 

L{Datum} or L{a_f2Tuple}) or C{None}. 

@kwarg adjust: Adjust the wrapped, unrolled longitudinal 

delta by the cosine of the mean latitude 

C{bool}). 

@kwarg wrap: Wrap and unroll longitudes (C{bool}). 

 

@return: Distance (C{meter}, same units as B{C{radius}} or the 

ellipsoid or datum axes or C{radians I{squared}} if 

B{C{radius}} is C{None} or C{0}). 

 

@raise TypeError: The B{C{other}} is not a L{Geohash}, C{LatLon} 

or C{str} or invalid B{C{radius}}. 

 

@see: U{Local, flat earth approximation 

<https://www.EdWilliams.org/avform.htm#flat>}, functions 

''' 

lls = self.latlon + _2Geohash(other).latlon 

kwds = dict(adjust=adjust, limit=None, wrap=wrap) 

return equirectangular( *lls, radius=radius, **kwds) if radius else \ 

_equirectangular_(*lls, **kwds).distance2 

 

def euclideanTo(self, other, radius=R_M, adjust=False, wrap=False): 

'''Approximate the distance between this and an other geohash 

using the L{euclidean} function. 

 

@arg other: The other geohash (L{Geohash}, C{LatLon} or C{str}). 

@kwarg radius: Mean earth radius, ellipsoid or datum 

(C{meter}, L{Ellipsoid}, L{Ellipsoid2}, 

L{Datum} or L{a_f2Tuple}). 

@kwarg adjust: Adjust the wrapped, unrolled longitudinal 

delta by the cosine of the mean latitude 

C{bool}). 

@kwarg wrap: Wrap and unroll longitudes (C{bool}). 

 

@return: Distance (C{meter}, same units as B{C{radius}} or the 

ellipsoid or datum axes). 

 

@raise TypeError: The B{C{other}} is not a L{Geohash}, C{LatLon} 

or C{str} or invalid B{C{radius}}. 

''' 

return self._distanceTo(euclidean, other, radius=radius, 

adjust=adjust, wrap=wrap) 

 

def haversineTo(self, other, radius=R_M, wrap=False): 

'''Compute the distance between this and an other geohash using 

the L{haversine} formula. 

 

@arg other: The other geohash (L{Geohash}, C{LatLon} or C{str}). 

@kwarg radius: Mean earth radius, ellipsoid or datum 

(C{meter}, L{Ellipsoid}, L{Ellipsoid2}, 

L{Datum} or L{a_f2Tuple}). 

@kwarg wrap: Wrap and unroll longitudes (C{bool}). 

 

@return: Distance (C{meter}, same units as B{C{radius}} or the 

ellipsoid or datum axes). 

 

@raise TypeError: The B{C{other}} is not a L{Geohash}, C{LatLon} 

or C{str} or invalid B{C{radius}}. 

''' 

return self._distanceTo(haversine, other, radius=radius, wrap=wrap) 

 

@Property_RO 

def latlon(self): 

'''Get the lat- and longitude of (the approximate center of) 

this geohash as a L{LatLon2Tuple}C{(lat, lon)} in C{degrees}. 

''' 

lat, lon = self._latlon or _2center(self.bounds()) 

return LatLon2Tuple(lat, lon, name=self.name) 

 

@Property_RO 

def neighbors(self): 

'''Get all 8 adjacent cells as a L{Neighbors8Dict}C{(N, NE, 

E, SE, S, SW, W, NW)} of L{Geohash}es. 

''' 

return Neighbors8Dict(N=self.N, NE=self.NE, E=self.E, SE=self.SE, 

S=self.S, SW=self.SW, W=self.W, NW=self.NW, 

name=self.name) 

 

@Property_RO 

def philam(self): 

'''Get the lat- and longitude of (the approximate center of) 

this geohash as a L{PhiLam2Tuple}C{(phi, lam)} in C{radians}. 

''' 

return PhiLam2Tuple(*map2(radians, self.latlon), name=self.name) 

 

@Property_RO 

def precision(self): 

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

''' 

return len(self) 

 

@Property_RO 

def sizes(self): 

'''Get the lat- and longitudinal size of this cell as 

a L{LatLon2Tuple}C{(lat, lon)} in (C{meter}). 

''' 

z = _GH.Sizes 

n = min(len(z) - 1, max(self.precision, 1)) 

return LatLon2Tuple(*z[n][:2], name=self.name) # XXX Height, Width? 

 

def toLatLon(self, LatLon=None, **LatLon_kwds): 

'''Return (the approximate center of) this geohash cell 

as an instance of the supplied C{LatLon} class. 

 

@arg LatLon: Class to use (C{LatLon}) or C{None}. 

@kwarg LatLon_kwds: Optional, additional B{C{LatLon}} 

keyword arguments, ignored if 

C{B{LatLon}=None}. 

 

@return: This geohash location (B{C{LatLon}}) or a 

L{LatLon2Tuple}C{(lat, lon)} if B{C{LatLon}} 

is C{None}. 

 

@raise TypeError: Invalid B{C{LatLon}} or B{C{LatLon_kwds}}. 

 

@example: 

 

>>> from sphericalTrigonometry import LatLon 

>>> ll = Geohash('u120fxw').toLatLon(LatLon) 

>>> print(repr(ll)) # LatLon(52°12′17.9″N, 000°07′07.64″E) 

>>> print(ll) # 52.204971°N, 000.11879°E 

''' 

return self.latlon if LatLon is None else _xnamed(LatLon( 

*self.latlon, **LatLon_kwds), self.name) 

 

def vincentysTo(self, other, radius=R_M, wrap=False): 

'''Compute the distance between this and an other geohash using 

the L{vincentys} formula. 

 

@arg other: The other geohash (L{Geohash}, C{LatLon} or C{str}). 

@kwarg radius: Mean earth radius, ellipsoid or datum 

(C{meter}, L{Ellipsoid}, L{Ellipsoid2}, 

L{Datum} or L{a_f2Tuple}). 

@kwarg wrap: Wrap and unroll longitudes (C{bool}). 

 

@return: Distance (C{meter}, same units as B{C{radius}} or the 

ellipsoid or datum axes). 

 

@raise TypeError: The B{C{other}} is not a L{Geohash}, C{LatLon} 

or C{str} or invalid B{C{radius}}. 

''' 

return self._distanceTo(vincentys, other, radius=radius, wrap=wrap) 

 

@Property_RO 

def N(self): 

'''Get the cell North of this (L{Geohash}). 

''' 

return self.adjacent(_N_) 

 

@Property_RO 

def S(self): 

'''Get the cell South of this (L{Geohash}). 

''' 

return self.adjacent(_S_) 

 

@Property_RO 

def E(self): 

'''Get the cell East of this (L{Geohash}). 

''' 

return self.adjacent(_E_) 

 

@Property_RO 

def W(self): 

'''Get the cell West of this (L{Geohash}). 

''' 

return self.adjacent(_W_) 

 

@Property_RO 

def NE(self): 

'''Get the cell NorthEast of this (L{Geohash}). 

''' 

return self.N.E 

 

@Property_RO 

def NW(self): 

'''Get the cell NorthWest of this (L{Geohash}). 

''' 

return self.N.W 

 

@Property_RO 

def SE(self): 

'''Get the cell SouthEast of this (L{Geohash}). 

''' 

return self.S.E 

 

@Property_RO 

def SW(self): 

'''Get the cell SouthWest of this (L{Geohash}). 

''' 

return self.S.W 

 

 

class GeohashError(_ValueError): 

'''Geohash encode, decode or other L{Geohash} issue. 

''' 

pass 

 

 

class Neighbors8Dict(_NamedDict): 

'''8-Dict C{(N, NE, E, SE, S, SW, W, NW)} of L{Geohash}es, 

providing key I{and} attribute access to the items. 

''' 

_Keys_ = (_N_, _NE_, _E_, _SE_, _S_, _SW_, _W_, _NW_) 

 

def __init__(self, **kwds): # PYCHOK no *args 

kwds = _xkwds(kwds, **_Neighbors8Defaults) 

_NamedDict.__init__(self, **kwds) # name=... 

 

 

_Neighbors8Defaults = dict(zip(Neighbors8Dict._Keys_, (None,) * 

len(Neighbors8Dict._Keys_))) # XXX frozendict 

 

 

def bounds(geohash, LatLon=None, **LatLon_kwds): 

'''Returns the lower-left SW and upper-right NE corners of a geohash. 

 

@arg geohash: To be bound (L{Geohash}). 

@kwarg LatLon: Optional class to return the bounds (C{LatLon}) 

or C{None}. 

@kwarg LatLon_kwds: Optional keyword arguments for B{C{LatLon}}, 

ignored if C{B{LatLon}=None}. 

 

@return: A L{Bounds2Tuple}C{(latlonSW, latlonNE)} of B{C{LatLon}}s 

or if B{C{LatLon}} is C{None}, a L{Bounds4Tuple}C{(latS, 

lonW, latN, lonE)}. 

 

@raise TypeError: The B{C{geohash}} is not a L{Geohash}, C{LatLon} 

or C{str} or invalid B{C{LatLon}} or invalid 

B{C{LatLon_kwds}}. 

 

@raise GeohashError: Invalid or C{null} B{C{geohash}}. 

 

@example: 

 

>>> geohash.bounds('u120fxw') # 52.20428467, 0.11810303, 52.20565796, 0.11947632 

>>> geohash.decode('u120fxw') # '52.205', '0.1188' 

''' 

gh = _2Geohash(geohash) 

if len(gh) < 1: 

raise GeohashError(geohash=geohash) 

 

s, w, n, e = _GH.Bounds4 

try: 

d = True 

for c in gh.lower(): 

i = _GH.DecodedBase32[c] 

for m in (16, 8, 4, 2, 1): 

if d: # longitude 

if i & m: 

w = favg(w, e) 

else: 

e = favg(w, e) 

else: # latitude 

if i & m: 

s = favg(s, n) 

else: 

n = favg(s, n) 

d = not d 

except KeyError: 

raise GeohashError(geohash=geohash) 

 

return _2bounds(LatLon, LatLon_kwds, s, w, n, e, 

name=nameof(geohash)) 

 

 

def _bounds3(geohash): 

'''(INTERNAL) Return 3-tuple C{(bounds, height, width)}. 

''' 

b = bounds(geohash) 

return b, (b.latN - b.latS), (b.lonE - b.lonW) 

 

 

def decode(geohash): 

'''Decode a geohash to lat-/longitude of the (approximate 

centre of) geohash cell to reasonable precision. 

 

@arg geohash: To be decoded (L{Geohash}). 

 

@return: 2-Tuple C{(latStr, lonStr)}, both C{str}. 

 

@raise TypeError: The B{C{geohash}} is not a L{Geohash}, 

C{LatLon} or C{str}. 

 

@raise GeohashError: Invalid or null B{C{geohash}}. 

 

@example: 

 

>>> geohash.decode('u120fxw') # '52.205', '0.1188' 

>>> geohash.decode('sunny') # '23.708', '42.473' Saudi Arabia 

>>> geohash.decode('fur') # '69.6', '-45.7' Greenland 

>>> geohash.decode('reef') # '-24.87', '162.95' Coral Sea 

>>> geohash.decode('geek') # '65.48', '-17.75' Iceland 

''' 

b, h, w = _bounds3(geohash) 

lat, lon = _2center(b) 

 

# round to near centre without excessive precision to 

# ⌊2-log10(Δ°)⌋ decimal places, strip trailing zeros 

return (fstr(lat, prec=int(2 - log10(h))), 

fstr(lon, prec=int(2 - log10(w)))) # strs! 

 

 

def decode2(geohash, LatLon=None, **LatLon_kwds): 

'''Decode a geohash to lat-/longitude of the (approximate 

centre of) geohash cell to reasonable precision. 

 

@arg geohash: To be decoded (L{Geohash}). 

@kwarg LatLon: Optional class to return the location (C{LatLon}) 

or C{None}. 

@kwarg LatLon_kwds: Optional keyword arguments for B{C{LatLon}}, 

ignored if C{B{LatLon}=None}. 

 

@return: L{LatLon2Tuple}C{(lat, lon)}, both C{degrees} if 

C{B{LatLon}=None}, otherwise a B{C{LatLon}} instance. 

 

@raise TypeError: The B{C{geohash}} is not a L{Geohash}, 

C{LatLon} or C{str}. 

 

@raise GeohashError: Invalid or null B{C{geohash}}. 

''' 

t = map2(float, decode(geohash)) 

r = LatLon2Tuple(*t) if LatLon is None else LatLon(*t, **LatLon_kwds) 

return _xnamed(r, decode2.__name__) 

 

 

def decode_error(geohash): 

'''Return the relative lat-/longitude decoding errors for 

this geohash. 

 

@arg geohash: To be decoded (L{Geohash}). 

 

@return: A L{LatLon2Tuple}C{(lat, lon)} with the lat- and 

longitudinal errors in (C{degrees}). 

 

@raise TypeError: The B{C{geohash}} is not a L{Geohash}, 

C{LatLon} or C{str}. 

 

@raise GeohashError: Invalid or null B{C{geohash}}. 

 

@example: 

 

>>> geohash.decode_error('u120fxw') # 0.00068665, 0.00068665 

>>> geohash.decode_error('fur') # 0.703125, 0.703125 

>>> geohash.decode_error('fu') # 2.8125, 5.625 

>>> geohash.decode_error('f') # 22.5, 22.5 

''' 

_, h, w = _bounds3(geohash) 

return LatLon2Tuple(h * _0_5, # Height error 

w * _0_5) # Width error 

 

 

def distance_(geohash1, geohash2): 

'''Estimate the distance between two geohash (from the cell sizes). 

 

@arg geohash1: First geohash (L{Geohash}, C{LatLon} or C{str}). 

@arg geohash2: Second geohash (L{Geohash}, C{LatLon} or C{str}). 

 

@return: Approximate distance (C{meter}). 

 

@raise TypeError: If B{C{geohash1}} or B{C{geohash2}} is 

not a L{Geohash}, C{LatLon} or C{str}. 

 

@example: 

 

>>> geohash.distance_('u120fxwsh', 'u120fxws0') # 15.239 

''' 

return _2Geohash(geohash1).distanceTo(geohash2) 

 

 

@deprecated_function 

def distance1(geohash1, geohash2): 

'''DEPRECATED, used L{geohash.distance_}.''' 

return distance_(geohash1, geohash2) 

 

 

@deprecated_function 

def distance2(geohash1, geohash2): 

'''DEPRECATED, used L{geohash.equirectangular_}.''' 

return equirectangular_(geohash1, geohash2) 

 

 

@deprecated_function 

def distance3(geohash1, geohash2): 

'''DEPRECATED, used L{geohash.haversine_}.''' 

return haversine_(geohash1, geohash2) 

 

 

def encode(lat, lon, precision=None): 

'''Encode a lat-/longitude as a C{geohash}, either to the specified 

precision or if not provided, to an automatically evaluated 

precision. 

 

@arg lat: Latitude (C{degrees}). 

@arg lon: Longitude (C{degrees}). 

@kwarg precision: Optional, the desired geohash length (C{int} 

1..12). 

 

@return: The C{geohash} (C{str}). 

 

@raise GeohashError: Invalid B{C{lat}}, B{C{lon}} or B{C{precision}}. 

 

@example: 

 

>>> geohash.encode(52.205, 0.119, 7) # 'u120fxw' 

>>> geohash.encode(52.205, 0.119, 12) # 'u120fxwshvkg' 

>>> geohash.encode(52.205, 0.1188, 12) # 'u120fxws0jre' 

>>> geohash.encode(52.205, 0.1188) # 'u120fxw' 

>>> geohash.encode( 0, 0) # 's00000000000' 

''' 

lat, lon = _2fll(lat, lon) 

 

if precision is None: 

# Infer precision by refining geohash until 

# it matches precision of supplied lat/lon. 

for p in range(1, _MaxPrec + 1): 

gh = encode(lat, lon, p) 

ll = map2(float, decode(gh)) 

if abs(lat - ll[0]) < EPS and \ 

abs(lon - ll[1]) < EPS: 

return gh 

p = _MaxPrec 

else: 

p = Precision_(precision, Error=GeohashError, low=1, high=_MaxPrec) 

 

b = i = 0 

d, gh = True, [] 

s, w, n, e = _GH.Bounds4 

 

while p > 0: 

i += i 

if d: # bisect longitude 

m = favg(e, w) 

if lon < m: 

e = m 

else: 

w = m 

i += 1 

else: # bisect latitude 

m = favg(n, s) 

if lat < m: 

n = m 

else: 

s = m 

i += 1 

d = not d 

 

b += 1 

if b == 5: 

# 5 bits gives a character: 

# append it and start over 

gh.append(_GH.GeohashBase32[i]) 

b = i = 0 

p -= 1 

 

return NN.join(gh) 

 

 

def equirectangular_(geohash1, geohash2, radius=R_M): 

'''Approximate the distance between two geohashes using the 

L{equirectangular} formula. 

 

@arg geohash1: First geohash (L{Geohash}, C{LatLon} or C{str}). 

@arg geohash2: Second geohash (L{Geohash}, C{LatLon} or C{str}). 

@kwarg radius: Mean earth radius (C{meter}) or C{None}. 

 

@return: Approximate distance (C{meter}, same units as 

B{C{radius}}). 

 

@raise TypeError: If B{C{geohash1}} or B{C{geohash2}} is 

not a L{Geohash}, C{LatLon} or C{str}. 

 

@example: 

 

>>> geohash.equirectangular_('u120fxwsh', 'u120fxws0') # 19.0879 

''' 

return _2Geohash(geohash1).equirectangularTo(geohash2, radius=radius) 

 

 

def haversine_(geohash1, geohash2, radius=R_M): 

'''Compute the great-circle distance between two geohashes 

using the L{haversine} formula. 

 

@arg geohash1: First geohash (L{Geohash}, C{LatLon} or C{str}). 

@arg geohash2: Second geohash (L{Geohash}, C{LatLon} or C{str}). 

@kwarg radius: Mean earth radius (C{meter}). 

 

@return: Great-circle distance (C{meter}, same units as 

B{C{radius}}). 

 

@raise TypeError: If B{C{geohash1}} or B{C{geohash2}} is 

not a L{Geohash}, C{LatLon} or C{str}. 

 

@example: 

 

>>> geohash.haversine_('u120fxwsh', 'u120fxws0') # 11.6978 

''' 

return _2Geohash(geohash1).haversineTo(geohash2, radius=radius) 

 

 

def neighbors(geohash): 

'''Return the L{Geohash}es for all 8 adjacent cells. 

 

@arg geohash: Cell for which neighbors are requested 

(L{Geohash} or C{str}). 

 

@return: A L{Neighbors8Dict}C{(N, NE, E, SE, S, SW, W, NW)} 

of L{Geohash}es. 

 

@raise TypeError: The B{C{geohash}} is not a L{Geohash}, 

C{LatLon} or C{str}. 

 

@JSname: I{neighbours}. 

''' 

return _2Geohash(geohash).neighbors 

 

 

def precision(res1, res2=None): 

'''Determine the L{Geohash} precisions to meet a or both given 

(geographic) resolutions. 

 

@arg res1: The required primary I{(longitudinal)} resolution 

(C{degrees}). 

@kwarg res2: Optional, required secondary I{(latitudinal)} 

resolution (C{degrees}). 

 

@return: The L{Geohash} precision or length (C{int}, 1..12). 

 

@raise GeohashError: Invalid B{C{res1}} or B{C{res2}}. 

 

@see: C++ class U{Geohash 

<https://GeographicLib.SourceForge.io/html/classGeographicLib_1_1Geohash.html>}. 

''' 

r = Degrees_(res1=res1, low=_0_0, Error=GeohashError) 

if res2 is None: 

t = r, r 

for p in range(1, _MaxPrec): 

if resolution2(p, None) <= t: 

return p 

 

else: 

t = r, Degrees_(res2=res2, low=_0_0, Error=GeohashError) 

for p in range(1, _MaxPrec): 

if resolution2(p, p) <= t: 

return p 

 

return _MaxPrec 

 

 

class Resolutions2Tuple(_NamedTuple): 

'''2-Tuple C{(res1, res2)} with the primary I{(longitudinal)} and 

secondary I{(latitudinal)} resolution, both in C{degrees}. 

''' 

_Names_ = ('res1', 'res2') 

_Units_ = ( Degrees_, Degrees_) 

 

 

def resolution2(prec1, prec2=None): 

'''Determine the (geographic) resolutions of given L{Geohash} 

precisions. 

 

@arg prec1: The given primary I{(longitudinal)} precision 

(C{int} 1..12). 

@kwarg prec2: Optional, secondary I{(latitudinal)} precision 

(C{int} 1..12). 

 

@return: L{Resolutions2Tuple}C{(res1, res2)} with the 

(geographic) resolutions C{degrees}, where C{res2} 

B{C{is}} C{res1} if no B{C{prec2}} is given. 

 

@raise GeohashError: Invalid B{C{prec1}} or B{C{prec2}}. 

 

@see: I{Karney}'s C++ class U{Geohash 

<https://GeographicLib.SourceForge.io/html/classGeographicLib_1_1Geohash.html>}. 

''' 

res1, res2 = _360_0, _180_0 # note ... lon, lat! 

 

if prec1: 

p = 5 * max(0, min(Int(prec1=prec1, Error=GeohashError), _MaxPrec)) 

res1 = res2 = ldexp(res1, -(p - p // 2)) 

 

if prec2: 

p = 5 * max(0, min(Int(prec2=prec2, Error=GeohashError), _MaxPrec)) 

res2 = ldexp(res2, -(p // 2)) 

 

return Resolutions2Tuple(res1, res2) 

 

 

def sizes(geohash): 

'''Return the lat- and longitudinal size of this L{Geohash} cell. 

 

@arg geohash: Cell for which size are required (L{Geohash} or 

C{str}). 

 

@return: A L{LatLon2Tuple}C{(lat, lon)} with the latitudinal 

height and longitudinal width in (C{meter}). 

 

@raise TypeError: The B{C{geohash}} is not a L{Geohash}, 

C{LatLon} or C{str}. 

''' 

return _2Geohash(geohash).sizes 

 

 

__all__ += _ALL_OTHER(bounds, # functions 

decode, decode2, decode_error, distance_, 

encode, equirectangular_, haversine_, 

neighbors, precision, resolution2, sizes) 

 

# **) MIT License 

# 

# Copyright (C) 2016-2021 -- 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.