The django.contrib.gis.measure module contains objects that allow\nfor convenient representation of distance and area units of measure. [1]\nSpecifically, it implements two objects, Distance and\nArea – both of which may be accessed via the\nD and A convenience aliases, respectively.
Distance objects may be instantiated using a keyword argument indicating the\ncontext of the units. In the example below, two different distance objects are\ninstantiated in units of kilometers (km) and miles (mi):
>>> from django.contrib.gis.measure import Distance, D\n>>> d1 = Distance(km=5)\n>>> print(d1)\n5.0 km\n>>> d2 = D(mi=5) # `D` is an alias for `Distance`\n>>> print(d2)\n5.0 mi\nConversions are easy, just access the preferred unit attribute to get a\nconverted distance quantity:
\n>>> print(d1.mi) # Converting 5 kilometers to miles\n3.10685596119\n>>> print(d2.km) # Converting 5 miles to kilometers\n8.04672\nMoreover, arithmetic operations may be performed between the distance\nobjects:
\n>>> print(d1 + d2) # Adding 5 miles to 5 kilometers\n13.04672 km\n>>> print(d2 - d1) # Subtracting 5 kilometers from 5 miles\n1.89314403881 mi\nTwo Distance objects multiplied together will yield an Area\nobject, which uses squared units of measure:
>>> a = d1 * d2 # Returns an Area object.\n>>> print(a)\n40.2336 sq_km\nTo determine what the attribute abbreviation of a unit is, the unit_attname\nclass method may be used:
>>> print(Distance.unit_attname('US Survey Foot'))\nsurvey_ft\n>>> print(Distance.unit_attname('centimeter'))\ncm\nUnit Attribute | \nFull name or alias(es) | \n
|---|---|
| \nKilometre, Kilometer | \n
| \nMile | \n
| \nMeter, Metre | \n
| \nYard | \n
| \nFoot, Foot (International) | \n
| \nU.S. Foot, US survey foot | \n
| \nInches | \n
| \nCentimeter | \n
| \nMillimetre, Millimeter | \n
| \nMicrometer, Micrometre | \n
| \nBritish foot (Sears 1922) | \n
| \nBritish yard (Sears 1922) | \n
| \nBritish chain (Sears 1922) | \n
| \nIndian yard, Yard (Indian) | \n
| \nYard (Sears) | \n
| \nClarke’s Foot | \n
| \nChain | \n
| \nChain (Benoit) | \n
| \nChain (Sears) | \n
| \nBritish chain (Benoit 1895 B) | \n
| \nBritish chain (Sears 1922 truncated) | \n
| \nGold Coast foot | \n
| \nLink | \n
| \nLink (Benoit) | \n
| \nLink (Sears) | \n
| \nClarke’s link | \n
| \nFathom | \n
| \nRod | \n
| \nNautical Mile | \n
| \nNautical Mile (UK) | \n
| \nGerman legal metre | \n
DistanceLink to this heading#To initialize a distance object, pass in a keyword corresponding to the\ndesired unit attribute name set with desired\nvalue. For example, the following creates a distance object representing 5\nmiles:
\n>>> dist = Distance(mi=5)\nReturns the distance value in units corresponding to the given unit\nattribute. For example:
\n>>> print(dist.km)\n8.04672\nReturns the distance unit attribute name for the given full unit name. For\nexample:
\n>>> Distance.unit_attname('Mile')\n'mi'\nAlias for Distance class.
AreaLink to this heading#To initialize an area object, pass in a keyword corresponding to the\ndesired unit attribute name set with desired\nvalue. For example, the following creates an area object representing 5\nsquare miles:
\n>>> a = Area(sq_mi=5)\nReturns the area value in units corresponding to the given unit attribute.\nFor example:
\n>>> print(a.sq_km)\n12.949940551680001\nReturns the area unit attribute name for the given full unit name. For\nexample:
\n>>> Area.unit_attname('Kilometer')\n'sq_km'\nAlias for Area class.
Footnotes
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