#31087: SpatialLite backend raises ValueError when getting distance parameter
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Reporter: tcourtqtm | Owner: nobody
Type: Bug | Status: new
Component: GIS | Version: 2.2
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 0
UI/UX: 0 |
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I'm experiencing a `ValueError` from the SpatiaLite backend. When doing a
query like this:
`MyModel.objects.filter(point__dwithin = (some_point,
D(km=distance_in_km)))`
I am getting this error:
`ValueError: Only numeric values of degree units are allowed on geographic
DWithin queries.`
This does not happen with the PostGIS backend and I believe it's a bug.
After a bit of searching I noticed that the difference between the two
backends is that postgis has a conditional to check if the PointField is
geographic and, if it is, avoids the exception.
The
[https://github.com/django/django/blob/738e9e615dc81b561c9fb01439119f4475c2e25b/django/contrib/gis/db/backends/postgis/operations.py#L255
code from the postgis backend]:
{{{
if isinstance(value, Distance):
if geography:
dist_param = value.m
elif geodetic:
if lookup_type == 'dwithin':
raise ValueError('Only numeric values of degree units
are '
'allowed on geographic DWithin
queries.')
dist_param = value.m
else:
dist_param = getattr(value,
Distance.unit_attname(f.units_name(self.connection)))
}}}
And the
[https://github.com/django/django/blob/738e9e615dc81b561c9fb01439119f4475c2e25b/django/contrib/gis/db/backends/spatialite/operations.py#L131
same function from the spatialite backend]:
{{{
if isinstance(value, Distance):
if f.geodetic(self.connection):
if lookup_type == 'dwithin':
raise ValueError(
'Only numeric values of degree units are allowed
on '
'geographic DWithin queries.'
)
dist_param = value.m
else:
dist_param = getattr(value,
Distance.unit_attname(f.units_name(self.connection)))
}}}
I am very unfamiliar with Geo stuff in general but this looks like a
simple omission in the spatialite code. I believe it should have a similar
`if geography` check.
--
Ticket URL: <https://code.djangoproject.com/ticket/31087>
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