id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
25605	GIS functions don't work with left-hand-side expressions	Sergey Fedoseev	Sergey Fedoseev	"geotest/models.py:
{{{
class Test(models.Model):
    point1 = models.PointField()
    point2 = models.PointField()
}}}

python manage.py shell

{{{
In [1]: %paste                                                                                                                                                               
from django.contrib.gis.db.models.functions import Distance
from django.contrib.gis.geos import Point

from geotest.models import Test

point1 = Point(0, 0, srid=4326)
point2 = Point(0, 1, srid=4326)
Test.objects.create(point1=point1, point2=point2)

## -- End pasted text --
Out[1]: <Test: Test object>

In [2]: print Test.objects.annotate(dist=Distance('point1', point2)).last().dist
111195.079735 m

In [3]: print Test.objects.annotate(dist=Distance(point1, 'point2')).last().dist
GEOS_ERROR: ParseException: Unknown type: 'POINT2'

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-3-aa91ca51a4df> in <module>()
----> 1 print Test.objects.annotate(dist=Distance(point1, 'point2')).last().dist

/home/sergey/dev/django/django/contrib/gis/db/models/functions.pyc in __init__(self, expr1, expr2, spheroid, **extra)
    239             self.spheroid = spheroid
    240             expressions += (self._handle_param(spheroid, 'spheroid', bool),)
--> 241         super(Distance, self).__init__(*expressions, **extra)
    242 
    243     def as_postgresql(self, compiler, connection):

/home/sergey/dev/django/django/contrib/gis/db/models/functions.pyc in __init__(self, expression, geom, *expressions, **extra)
     97                 geom = GEOSGeometry(geom)
     98             except Exception:
---> 99                 raise ValueError(""This function requires a geometric parameter."")
    100         if not geom.srid:
    101             raise ValueError(""Please provide a geometry attribute with a defined SRID."")

ValueError: This function requires a geometric parameter.

In [4]: print Test.objects.annotate(dist=Distance('point1', 'point2')).last().dist
GEOS_ERROR: ParseException: Unknown type: 'POINT2'

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-4-177990c7d19a> in <module>()
----> 1 print Test.objects.annotate(dist=Distance('point1', 'point2')).last().dist

/home/sergey/dev/django/django/contrib/gis/db/models/functions.pyc in __init__(self, expr1, expr2, spheroid, **extra)
    239             self.spheroid = spheroid
    240             expressions += (self._handle_param(spheroid, 'spheroid', bool),)
--> 241         super(Distance, self).__init__(*expressions, **extra)
    242 
    243     def as_postgresql(self, compiler, connection):

/home/sergey/dev/django/django/contrib/gis/db/models/functions.pyc in __init__(self, expression, geom, *expressions, **extra)
     97                 geom = GEOSGeometry(geom)
     98             except Exception:
---> 99                 raise ValueError(""This function requires a geometric parameter."")
    100         if not geom.srid:
    101             raise ValueError(""Please provide a geometry attribute with a defined SRID."")

ValueError: This function requires a geometric parameter.
}}}
"	Bug	closed	GIS	dev	Normal	fixed			Accepted	1	0	0	0	0	0