Django django.contrib.gis.db.models.functions.Distance 到 return 值以英尺而不是米为单位

Question

以下代码将正确过滤：

def nearby(self, latitude, longitude, proximity=None):
        """Get nearby Merchants.

        Custom queryset method for getting merchants associated with
        nearby places.

        Returns:
            A queryset of ``Merchant`` objects.

        """
        point = Point(latitude, longitude)

        # we query for location nearby for places first and then
        # annotate with distance to the same place
        return self.filter(
            places__location__distance_lte=(point, D(ft=proximity))
        ).annotate(distance=models.Min(Distance('places__location', point)))

但是

返回的值

models.Min(Distance('places__location', point))

以米为单位。

能不能换成英尺？

Answer 1

如果我们看一下 Distance documentation，我们会看到：

Because the distance attribute is a Distance object, you can easily express the value in the units of your choice.

虽然这不是:

Those two aren't that closely related to each other. Docs do indeed say that it "returns" Distance object, but there is an extra step:

django.contrib.gis.db.models.functions.Distance is a database function, it takes two expressions (that may include database field names) and returns a Func object that can be used as a part of a query.

So simply put, it needs to be executed in a database. It will calculate distance using database function (e.g. postgis ST_Distance) and then bring it back as a django.contrib.gis.measure.Distance object

综上所述，你可以这样做：

... .annotate(distance=models.Min(Distance('places__location', point).ft))

Django django.contrib.gis.db.models.functions.Distance 到 return 值以英尺而不是米为单位

Django django.contrib.gis.db.models.functions.Distance to return values in feet instead of meters

python

django

python-3.x

django-orm