--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/app/django/contrib/gis/measure.py Tue Oct 14 16:00:59 2008 +0000
@@ -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