如何使用geodjango从一个点的最低距离返回一条记录？ [英] How to return a record with the lowest distance from a point using geodjango?

问题描述

我正在使用geodjango并在我的数据库中收集积分。要获得一定区域内的积分，请使用以下内容：

  queryset = Spot.objects.filter（point__distance_lte = ，distance_m））
  

我的问题是如何只返回一个点（与最低距离）从我过去的那一点起？

编辑

$ b $我应该提到我正在坐标坐标，并希望与他们一起创建一个 Point 对象。然后通过该点作为起点和过滤器。
例如我尝试过：

  from spots.models import * 
 from django.contrib.gis .geos import * 
 
 origin = Point（28.011030，-26.029430）
 distance_m = 1000 
 
 queryset = Spot.objects.filter（point__distance_lte =（origin，distance_m ））
 for q in queryset：
 print q.distance 
  

此代码段的代码给我这个错误：

 追溯（最近的最后一次呼叫）：
文件<控制台& ，第2行，< module> 
 AttributeError：'Spot'对象没有属性'distance'
  

有趣的是，如果我做以下：

  origin = Spot.objects.get（name ='Montecasino'）。point 
 distance_m = 1000 
 
 Spot.objects.distance（origin）中的城市
 print（city.name，city.distance）
 
（u'Design Quarter Parking'距离（m = 677.347841801））
（u'Montecasino'，距离（m = 0.0））
（u'Fourways'，距离（m = 1080.67723755））
  

解决方案

最后一个从 GeoDjango距离过滤器，距离值存储在模型中 - 查询，导致我 post 。根据这些信息，我可以收集您在距离查询中必须 measure参数。
您将在下面的代码段中看到，导入度量为D 。然后在查询中使用它。
如果你没有指定，你会得到这个错误：

  ValueError：`distance_lte`查询所需的元组类型。 
  

要使用我使用的最低距离的点 order_by（'distance '）[：1] [0]

  from spots.models import * 
来自django.contrib.gis.geos import * 
 from django.contrib.gis.measure import D 
 
 distance_m = 20000 
 origin = Point（28.011030，-26.029430）
 
 nearest_spot = Spot.objects.filter（point__distance_lte =（origin，D（m = distance_m）））。distance（origin）.order_by（'distance'）[：1] [0] 
  

I am using geodjango and have a collection of points in my database. To get a queryset of points within a certain area I use this:

queryset = Spot.objects.filter(point__distance_lte=(origin, distance_m))

My question is how can I return only one point(the point with the lowest distance)from the point I have passed it?

EDIT

I should mention that I am passing in coordinates and wanting to create a Point object with them. Then pass that point in as the origin and filter against that. For example I have tried:

from spots.models import *
from django.contrib.gis.geos import *

origin = Point(28.011030, -26.029430)
distance_m = 1000

queryset = Spot.objects.filter(point__distance_lte=(origin, distance_m))
for q in queryset:
    print q.distance

This snippet of code gives me this error:

Traceback (most recent call last):
  File "<console>", line 2, in <module>
AttributeError: 'Spot' object has no attribute 'distance'

Interestingly enough if I do the following:

origin = Spot.objects.get(name='Montecasino').point
distance_m = 1000

for city in Spot.objects.distance(origin):
    print(city.name, city.distance)

(u'Design Quarter Parking', Distance(m=677.347841801))
(u'Montecasino', Distance(m=0.0))
(u'Fourways', Distance(m=1080.67723755))

解决方案

Finally a solution gathered from clues from GeoDjango distance filter with distance value stored within model - query which lead me to this post. From this information I was able to gather that you MUST SPECIFY the measure parameter in your distance query. You will see in the below snippet, I import measure as D. Then use it in the query. If you don't specify it you will get this error:

ValueError: Tuple required for `distance_lte` lookup type.

To take just the point with the lowest distance I used order_by('distance')[:1][0]

from spots.models import *
from django.contrib.gis.geos import *
from django.contrib.gis.measure import D

distance_m = 20000
origin = Point(28.011030, -26.029430)

closest_spot = Spot.objects.filter(point__distance_lte=(origin, D(m=distance_m))).distance(origin).order_by('distance')[:1][0]

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