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Diffstat (limited to 'webapp/django/contrib/gis/measure.py')
| -rw-r--r-- | webapp/django/contrib/gis/measure.py | 329 |
1 files changed, 329 insertions, 0 deletions
diff --git a/webapp/django/contrib/gis/measure.py b/webapp/django/contrib/gis/measure.py new file mode 100644 index 0000000000..42c49ce154 --- /dev/null +++ b/webapp/django/contrib/gis/measure.py @@ -0,0 +1,329 @@ +# Copyright (c) 2007, Robert Coup <robert.coup@onetrackmind.co.nz> +# All rights reserved. +# +# Redistribution and use in source and binary forms, with or without modification, +# are permitted provided that the following conditions are met: +# +# 1. Redistributions of source code must retain the above copyright notice, +# this list of conditions and the following disclaimer. +# +# 2. Redistributions in binary form must reproduce the above copyright +# notice, this list of conditions and the following disclaimer in the +# documentation and/or other materials provided with the distribution. +# +# 3. Neither the name of Distance nor the names of its contributors may be used +# to endorse or promote products derived from this software without +# specific prior written permission. +# +# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND +# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED +# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE +# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR +# ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES +# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; +# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON +# ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS +# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +# +""" +Distance and Area objects to allow for sensible and convienient calculation +and conversions. + +Authors: Robert Coup, Justin Bronn + +Inspired by GeoPy (http://exogen.case.edu/projects/geopy/) +and Geoff Biggs' PhD work on dimensioned units for robotics. +""" +__all__ = ['A', 'Area', 'D', 'Distance'] +from decimal import Decimal + +class MeasureBase(object): + def default_units(self, kwargs): + """ + Return the unit value and the the default units specified + from the given keyword arguments dictionary. + """ + val = 0.0 + for unit, value in kwargs.iteritems(): + if unit in self.UNITS: + val += self.UNITS[unit] * value + default_unit = unit + elif unit in self.ALIAS: + u = self.ALIAS[unit] + val += self.UNITS[u] * value + default_unit = u + else: + lower = unit.lower() + if lower in self.UNITS: + val += self.UNITS[lower] * value + default_unit = lower + elif lower in self.LALIAS: + u = self.LALIAS[lower] + val += self.UNITS[u] * value + default_unit = u + else: + raise AttributeError('Unknown unit type: %s' % unit) + return val, default_unit + + @classmethod + def unit_attname(cls, unit_str): + """ + Retrieves the unit attribute name for the given unit string. + For example, if the given unit string is 'metre', 'm' would be returned. + An exception is raised if an attribute cannot be found. + """ + lower = unit_str.lower() + if unit_str in cls.UNITS: + return unit_str + elif lower in cls.UNITS: + return lower + elif lower in cls.LALIAS: + return cls.LALIAS[lower] + else: + raise Exception('Could not find a unit keyword associated with "%s"' % unit_str) + +class Distance(MeasureBase): + UNITS = { + 'chain' : 20.1168, + 'chain_benoit' : 20.116782, + 'chain_sears' : 20.1167645, + 'british_chain_benoit' : 20.1167824944, + 'british_chain_sears' : 20.1167651216, + 'british_chain_sears_truncated' : 20.116756, + 'cm' : 0.01, + 'british_ft' : 0.304799471539, + 'british_yd' : 0.914398414616, + 'clarke_ft' : 0.3047972654, + 'clarke_link' : 0.201166195164, + 'fathom' : 1.8288, + 'ft': 0.3048, + 'german_m' : 1.0000135965, + 'gold_coast_ft' : 0.304799710181508, + 'indian_yd' : 0.914398530744, + 'inch' : 0.0254, + 'km': 1000.0, + 'link' : 0.201168, + 'link_benoit' : 0.20116782, + 'link_sears' : 0.20116765, + 'm': 1.0, + 'mi': 1609.344, + 'mm' : 0.001, + 'nm': 1852.0, + 'nm_uk' : 1853.184, + 'rod' : 5.0292, + 'sears_yd' : 0.91439841, + 'survey_ft' : 0.304800609601, + 'um' : 0.000001, + 'yd': 0.9144, + } + + # Unit aliases for `UNIT` terms encountered in Spatial Reference WKT. + ALIAS = { + 'centimeter' : 'cm', + 'foot' : 'ft', + 'inches' : 'inch', + 'kilometer' : 'km', + 'kilometre' : 'km', + 'meter' : 'm', + 'metre' : 'm', + 'micrometer' : 'um', + 'micrometre' : 'um', + 'millimeter' : 'mm', + 'millimetre' : 'mm', + 'mile' : 'mi', + 'yard' : 'yd', + 'British chain (Benoit 1895 B)' : 'british_chain_benoit', + 'British chain (Sears 1922)' : 'british_chain_sears', + 'British chain (Sears 1922 truncated)' : 'british_chain_sears_truncated', + 'British foot (Sears 1922)' : 'british_ft', + 'British foot' : 'british_ft', + 'British yard (Sears 1922)' : 'british_yd', + 'British yard' : 'british_yd', + "Clarke's Foot" : 'clarke_ft', + "Clarke's link" : 'clarke_link', + 'Chain (Benoit)' : 'chain_benoit', + 'Chain (Sears)' : 'chain_sears', + 'Foot (International)' : 'ft', + 'German legal metre' : 'german_m', + 'Gold Coast foot' : 'gold_coast_ft', + 'Indian yard' : 'indian_yd', + 'Link (Benoit)': 'link_benoit', + 'Link (Sears)': 'link_sears', + 'Nautical Mile' : 'nm', + 'Nautical Mile (UK)' : 'nm_uk', + 'US survey foot' : 'survey_ft', + 'U.S. Foot' : 'survey_ft', + 'Yard (Indian)' : 'indian_yd', + 'Yard (Sears)' : 'sears_yd' + } + LALIAS = dict([(k.lower(), v) for k, v in ALIAS.items()]) + + def __init__(self, default_unit=None, **kwargs): + # The base unit is in meters. + self.m, self._default_unit = self.default_units(kwargs) + if default_unit and isinstance(default_unit, str): + self._default_unit = default_unit + + def __getattr__(self, name): + if name in self.UNITS: + return self.m / self.UNITS[name] + else: + raise AttributeError('Unknown unit type: %s' % name) + + def __repr__(self): + return 'Distance(%s=%s)' % (self._default_unit, getattr(self, self._default_unit)) + + def __str__(self): + return '%s %s' % (getattr(self, self._default_unit), self._default_unit) + + def __cmp__(self, other): + if isinstance(other, Distance): + return cmp(self.m, other.m) + else: + return NotImplemented + + def __add__(self, other): + if isinstance(other, Distance): + return Distance(default_unit=self._default_unit, m=(self.m + other.m)) + else: + raise TypeError('Distance must be added with Distance') + + def __iadd__(self, other): + if isinstance(other, Distance): + self.m += other.m + return self + else: + raise TypeError('Distance must be added with Distance') + + def __sub__(self, other): + if isinstance(other, Distance): + return Distance(default_unit=self._default_unit, m=(self.m - other.m)) + else: + raise TypeError('Distance must be subtracted from Distance') + + def __isub__(self, other): + if isinstance(other, Distance): + self.m -= other.m + return self + else: + raise TypeError('Distance must be subtracted from Distance') + + def __mul__(self, other): + if isinstance(other, (int, float, long, Decimal)): + return Distance(default_unit=self._default_unit, m=(self.m * float(other))) + elif isinstance(other, Distance): + return Area(default_unit='sq_' + self._default_unit, sq_m=(self.m * other.m)) + else: + raise TypeError('Distance must be multiplied with number or Distance') + + def __imul__(self, other): + if isinstance(other, (int, float, long, Decimal)): + self.m *= float(other) + return self + else: + raise TypeError('Distance must be multiplied with number') + + def __div__(self, other): + if isinstance(other, (int, float, long, Decimal)): + return Distance(default_unit=self._default_unit, m=(self.m / float(other))) + else: + raise TypeError('Distance must be divided with number') + + def __idiv__(self, other): + if isinstance(other, (int, float, long, Decimal)): + self.m /= float(other) + return self + else: + raise TypeError('Distance must be divided with number') + + def __nonzero__(self): + return bool(self.m) + +class Area(MeasureBase): + # Getting the square units values and the alias dictionary. + UNITS = dict([('sq_%s' % k, v ** 2) for k, v in Distance.UNITS.items()]) + ALIAS = dict([(k, 'sq_%s' % v) for k, v in Distance.ALIAS.items()]) + LALIAS = dict([(k.lower(), v) for k, v in ALIAS.items()]) + + def __init__(self, default_unit=None, **kwargs): + self.sq_m, self._default_unit = self.default_units(kwargs) + if default_unit and isinstance(default_unit, str): + self._default_unit = default_unit + + def __getattr__(self, name): + if name in self.UNITS: + return self.sq_m / self.UNITS[name] + else: + raise AttributeError('Unknown unit type: ' + name) + + def __repr__(self): + return 'Area(%s=%s)' % (self._default_unit, getattr(self, self._default_unit)) + + def __str__(self): + return '%s %s' % (getattr(self, self._default_unit), self._default_unit) + + def __cmp__(self, other): + if isinstance(other, Area): + return cmp(self.sq_m, other.sq_m) + else: + return NotImplemented + + def __add__(self, other): + if isinstance(other, Area): + return Area(default_unit=self._default_unit, sq_m=(self.sq_m + other.sq_m)) + else: + raise TypeError('Area must be added with Area') + + def __iadd__(self, other): + if isinstance(other, Area): + self.sq_m += other.sq_m + return self + else: + raise TypeError('Area must be added with Area') + + def __sub__(self, other): + if isinstance(other, Area): + return Area(default_unit=self._default_unit, sq_m=(self.sq_m - other.sq_m)) + else: + raise TypeError('Area must be subtracted from Area') + + def __isub__(self, other): + if isinstance(other, Area): + self.sq_m -= other.sq_m + return self + else: + raise TypeError('Area must be subtracted from Area') + + def __mul__(self, other): + if isinstance(other, (int, float, long, Decimal)): + return Area(default_unit=self._default_unit, sq_m=(self.sq_m * float(other))) + else: + raise TypeError('Area must be multiplied with number') + + def __imul__(self, other): + if isinstance(other, (int, float, long, Decimal)): + self.sq_m *= float(other) + return self + else: + raise TypeError('Area must be multiplied with number') + + def __div__(self, other): + if isinstance(other, (int, float, long, Decimal)): + return Area(default_unit=self._default_unit, sq_m=(self.sq_m / float(other))) + else: + raise TypeError('Area must be divided with number') + + def __idiv__(self, other): + if isinstance(other, (int, float, long, Decimal)): + self.sq_m /= float(other) + return self + else: + raise TypeError('Area must be divided with number') + + def __nonzero__(self): + return bool(self.sq_m) + +# Shortcuts +D = Distance +A = Area |