Re: [Django] #10594: distance(geom) results ambiguous when the PointField can be null
#10594: distance(geom) results ambiguous when the PointField can be null
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Reporter: whiteinge | Owner: nobody
Status: new | Milestone:
Component: GIS | Version: SVN
Resolution: | Keywords: distance queryset
Stage: Unreviewed | Has_patch: 1
Needs_docs: 0 | Needs_tests: 0
Needs_better_patch: 0 |
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Changes (by yourcelf):
* needs_better_patch: => 0
* has_patch: 0 => 1
* needs_tests: => 0
* needs_docs: => 0
Comment:
The problem seems to arise from line 49 in django/contrib/gis/measure.py
{{{
if not isinstance(value, float): value = float(value)
}}}
Where "value" is the value of the geometry field. If the field is null,
this becomes None, and propagates a ValueError up the stack resulting in
an empty queryset.
I'm attaching a patch which fixes this by altering the method which
constructs geometry objects out of the measurement attributes to instead
keep the attribute as "None" if the value is None.
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Ticket URL:
Django
[Django] #10594: distance(geom) results ambiguous when the PointField can be null
#10594: distance(geom) results ambiguous when the PointField can be null
---+
Reporter: whiteinge | Owner: nobody
Status: new| Milestone:
Component: GIS| Version: SVN
Keywords: distance queryset | Stage: Unreviewed
Has_patch: 0 |
---+
Given the following GIS model:
{{{
class SomeModel(models.Model):
location = models.PointField(null=True)
}}}
When populated with instances that both have and do not have location
information, doing a {{{distance(geom)}}} query yields unexpected results.
For example, {{{SomeModel.objects.distance(somePoint)}}} returns no
results at all.
{{{SomeModel.objects.filter(location__isnull=False).distance(somePoint)}}}
works as expected.
IMO, {{{distance(geom)}}} results that cannot calculate distance should
simply return None.
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Ticket URL:
Django
