外键关系的 GeoDjango 距离查询
我有以下模型（简化）
from django.contrib.gis.db import models as geomodels
modelB (geomodels.Model):
objects = geomodels.GeoManager()
modelA (geomodels.Model):
point = geomodels.PointField(unique=True)
mb = models.ForeignKey(modelB,related_name='modela')
objects = geomodels.GeoManager()
我试图找到所有 modelB 对象并按距给定位置的距离对它们进行排序（其中距离定义为给定位置与关联 modelA 的点对象之间的距离）。当我尝试运行查询时
modelB.objects.distance((loc, field_name='modela__point')
，收到一条错误消息，
TypeError: ST_Distance output only available on GeometryFields.
指出 loc 是一个 Point 对象。但是，当我运行查询时，
modelB.objects.filter(modela__point__distance_lte = (loc, 1000))
此查询可以正常工作，不会出现错误，并且符合预期。
知道错误可能是什么吗？我正在使用 django 1.2.4、PostGis 1.5.2、PostGres 8.4。
谢谢。
I have the following models (simplified)
from django.contrib.gis.db import models as geomodels
modelB (geomodels.Model):
objects = geomodels.GeoManager()
modelA (geomodels.Model):
point = geomodels.PointField(unique=True)
mb = models.ForeignKey(modelB,related_name='modela')
objects = geomodels.GeoManager()
I am trying to find all modelB objects and sort them by distance from a given location (where distance is defined as distance between a given location and the point object of associated modelA). When I try to run the query
modelB.objects.distance((loc, field_name='modela__point')
I get an error saying
TypeError: ST_Distance output only available on GeometryFields.
Note that loc is a Point object.However, when I run the query
modelB.objects.filter(modela__point__distance_lte = (loc, 1000))
this query works without error and as expected.
Any idea what the mistake could be? I am using django 1.2.4, PostGis 1.5.2, PostGres 8.4.
Thanks.
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对于第一个，您需要将其更改为：
如果您想查看所有 modelB 对象。
“.distance”用于计算距离字段并将其添加到 QuerySet（或 GeoQuerySet）的每个结果行。
For the first one, you will need to change it to:
if you want to see all modelB objects.
The ".distance" is used to calculate and add a distance field to each resulting row of the QuerySet (or GeoQuerySet).