def falsed2(self):
'''Get the easting and northing falsing (L{EasNor2Tuple}C{(easting, northing)}).
'''
e = n = 0
if self.falsed:
e = _FalseEasting # relative to central meridian
if self.hemisphere == _S_: # relative to equator
n = _FalseNorthing
return EasNor2Tuple(e, n)
def forward(self, lat, lon):
'''Convert an (ellipsoidal) geodetic location Cassini-Soldner
easting and northing.
@param lat: Latitude of the location (C{degrees90}).
@param lon: Longitude of the location (C{degrees180}).
@return: An L{EasNor2Tuple}C{(easting, northing)}.
'''
r = EasNor2Tuple(*self.forward4(lat, lon)[:2])
return self._xnamed(r)
def forward(self, lat, lon):
'''Convert an (ellipsoidal) geodetic location to Cassini-Soldner
easting and northing.
@arg lat: Latitude of the location (C{degrees90}).
@arg lon: Longitude of the location (C{degrees180}).
@return: An L{EasNor2Tuple}C{(easting, northing)}.
@see: Methods L{CassiniSoldner.forward4}, L{CassiniSoldner.reverse}
and L{CassiniSoldner.reverse4}.
'''
r = EasNor2Tuple(*self.forward4(lat, lon)[:2])
return self._xnamed(r)
def to2en(self, falsed=True):
'''Return easting and northing, falsed or unfalsed.
@keyword falsed: Return easting and northing falsed
(C{bool}), otherwise unfalsed.
@return: An L{EasNor2Tuple}C{(easting, northing)}.
'''
e, n = self.falsed2
if self.falsed and not falsed:
e, n = -e, -n
elif falsed and not self.falsed:
pass
else:
e = n = 0
return EasNor2Tuple(e + self.easting, n + self.northing)
def eastingnorthing2(self, falsed=True):
'''Return easting and northing, falsed or unfalsed.
@kwarg falsed: Return easting and northing falsed
(C{bool}), otherwise unfalsed.
@return: An L{EasNor2Tuple}C{(easting, northing)} in C{meter}s.
'''
e, n = self.falsed2
if self.falsed and not falsed:
e, n = -e, -n
elif falsed and not self.falsed:
pass
else:
e = n = 0
return EasNor2Tuple(Easting(e + self.easting, Error=self._Error),
Northing(n + self.northing, Error=self._Error))
def forward(self, lat, lon):
'''Convert an (ellipsoidal) geodetic location to Cassini-Soldner
easting and northing.
@arg lat: Latitude of the location (C{degrees90}).
@arg lon: Longitude of the location (C{degrees180}).
@return: An L{EasNor2Tuple}C{(easting, northing)}.
@see: Methods L{CassiniSoldner.forward4}, L{CassiniSoldner.reverse}
and L{CassiniSoldner.reverse4}.
@raise CSSError: Invalid B{C{lat}} or B{C{lon}}.
'''
t = self.forward4(lat, lon)
r = EasNor2Tuple(t.easting, t.northing)
return self._xnamed(r)
def _EasNor2Tuple(e, n):
'''(INTERNAL) Helper for L{parseOSGR} and L{toOsgr}.
'''
return EasNor2Tuple(Easting(e, Error=OSGRError),
Northing(n, Error=OSGRError))
def falsed2(self):
'''Get the easting and northing falsing (L{EasNor2Tuple}C{(easting, northing)}).
'''
f = _Falsing if self.falsed else 0
return EasNor2Tuple(f, f)
def toOsgr(latlon, lon=None, datum=Datums.WGS84, Osgr=Osgr, name=''):
'''Convert a lat-/longitude point to an OSGR coordinate.
@param latlon: Latitude (C{degrees}) or an (ellipsoidal)
geodetic C{LatLon} point.
@keyword lon: Optional longitude in degrees (scalar or C{None}).
@keyword datum: Optional datum to convert (C{Datum}).
@keyword Osgr: Optional (sub-)class to return the OSGR
coordinate (L{Osgr}) or C{None}.
@keyword name: Optional B{C{Osgr}} name (C{str}).
@return: The OSGR coordinate (B{C{Osgr}}) or an
L{EasNor2Tuple}C{(easting, northing)} if B{C{Osgr}}
is C{None}.
@raise TypeError: Non-ellipsoidal B{C{latlon}} or B{C{datum}}
conversion failed.
@raise OSGRError: Invalid B{C{latlon}} or B{C{lon}}.
@example:
>>> p = LatLon(52.65798, 1.71605)
>>> r = toOsgr(p) # TG 51409 13177
>>> # for conversion of (historical) OSGB36 lat-/longitude:
>>> r = toOsgr(52.65757, 1.71791, datum=Datums.OSGB36)
'''
if not isinstance(latlon, _LLEB):
# XXX fix failing _LLEB.convertDatum()
latlon = _LLEB(*parseDMS2(latlon, lon), datum=datum)
elif lon is not None:
raise OSGRError('%s not %s: %r' % ('lon', None, lon))
elif not name: # use latlon.name
name = nameof(latlon)
E = _OSGB36.ellipsoid
ll = _ll2datum(latlon, _OSGB36, 'latlon')
a, b = map1(radians, ll.lat, ll.lon)
sa, ca = sincos2(a)
s = E.e2s2(sa) # v, r = E.roc2_(sa, _F0); r = v / r
v = E.a * _F0 / sqrt(s) # nu
r = s / E.e12 # nu / rho == v / (v * E.e12 / s)
x2 = r - 1 # η2
ta = tan(a)
ca3, ca5 = fpowers(ca, 5, 3) # PYCHOK false!
ta2, ta4 = fpowers(ta, 4, 2) # PYCHOK false!
vsa = v * sa
I4 = (E.b * _F0 * _M(E.Mabcd, a) + _N0,
(vsa / 2) * ca,
(vsa / 24) * ca3 * fsum_(5, -ta2, 9 * x2),
(vsa / 720) * ca5 * fsum_(61, ta4, -58 * ta2))
V4 = (_E0,
(v * ca),
(v / 6) * ca3 * (r - ta2),
(v / 120) * ca5 * fdot((-18, 1, 14, -58), ta2, 5 + ta4, x2, ta2 * x2))
d, d2, d3, d4, d5, d6 = fpowers(b - _B0, 6) # PYCHOK false!
n = fdot(I4, 1, d2, d4, d6)
e = fdot(V4, 1, d, d3, d5)
if Osgr is None:
r = EasNor2Tuple(e, n)
else:
r = Osgr(e, n)
if lon is None and isinstance(latlon, _LLEB):
r._latlon = latlon # XXX weakref(latlon)?
return _xnamed(r, name)
def parseOSGR(strOSGR, Osgr=Osgr, name=''):
'''Parse an OSGR coordinate string to an Osgr instance.
Accepts standard OS Grid References like 'SU 387 148',
with or without whitespace separators, from 2- up to
10-digit references (1 m × 1 m square), or fully
numeric, comma-separated references in metres, for
example '438700,114800'.
@param strOSGR: An OSGR coordinate (C{str}).
@keyword Osgr: Optional (sub-)class to return the OSGR
coordinate (L{Osgr}) or C{None}.
@keyword name: Optional B{C{Osgr}} name (C{str}).
@return: The OSGR coordinate (B{C{Osgr}}) or an
L{EasNor2Tuple}C{(easting, northing)} if B{C{Osgr}}
is C{None}.
@raise OSGRError: Invalid B{C{strOSGR}}.
@example:
>>> g = parseOSGR('TG 51409 13177')
>>> str(g) # TG 51409 13177
>>> g = parseOSGR('TG5140913177')
>>> str(g) # TG 51409 13177
>>> g = parseOSGR('TG51409 13177')
>>> str(g) # TG 51409 13177
>>> g = parseOSGR('651409,313177')
>>> str(g) # TG 51409 13177
>>> g.toStr(prec=0) # 651409,313177
'''
def _c2i(G):
g = ord(G.upper()) - ord('A')
if g > 7:
g -= 1
return g
def _s2f(g):
return float(g.strip())
def _s2i(G, g):
g += '00000' # std to meter
return int(str(G) + g[:5])
s = strOSGR.strip()
try:
g = s.split(',')
if len(g) == 2: # "easting,northing"
if len(s) < 13:
raise ValueError # caught below
e, n = map(_s2f, g)
else: # "GR easting northing"
g, s = s[:2], s[2:].strip()
e, n = map(_c2i, g)
n, m = divmod(n, 5)
E = ((e - 2) % 5) * 5 + m
N = 19 - (e // 5) * 5 - n
if 0 > E or E > 6 or \
0 > N or N > 12:
raise ValueError # caught below
g = s.split()
if len(g) == 1: # no whitespace
e, n = halfs2(s)
elif len(g) == 2:
e, n = g
else:
raise ValueError # caught below
e = _s2i(E, e)
n = _s2i(N, n)
except ValueError:
raise OSGRError('%s invalid: %r' % ('strOSGR', strOSGR))
r = EasNor2Tuple(e, n) if Osgr is None else Osgr(e, n)
return _xnamed(r, name)
def eastingnorthing(self):
'''Get easting and northing (L{EasNor2Tuple}C{(easting, northing)}) in C{meter}s.
'''
return EasNor2Tuple(self.easting, self.northing)