使用 GeoDjango 获取相关位置字段

Question

我正在开发一个使用 GeoDjango 查找附近场地演出的小应用程序。这是我的 models.py:

from django.contrib.gis.db import models

class Venue(models.Model):
    """
    Model for a venue
    """
    name = models.CharField(max_length=200)
    location = models.PointField()

    def __str__(self):
        return self.name


class Event(models.Model):
    """
    Model for an event
    """
    name = models.CharField(max_length=200)
    datetime = models.DateTimeField()
    venue = models.ForeignKey(Venue)

    def __str__(self):
        return "%s - %s" % (self.name, self.venue.name)

现在，我已经设法让它进行查找，在我看来我需要将响应序列化为 geojson 以便在地图上呈现它。但是，我正在努力完成它。这是我目前的 views.py:

from django.shortcuts import render_to_response
from django.views.generic.edit import FormView
from gigs.forms import LookupForm
from gigs.models import Event
from django.utils import timezone
from django.contrib.gis.geos import Point
from django.contrib.gis.db.models.functions import Distance
from django.template import RequestContext

class LookupView(FormView):
    form_class = LookupForm

    def get(self, request):
        return render_to_response('gigs/lookup.html', RequestContext(request))

    def form_valid(self, form):
        # Get data
        latitude = form.cleaned_data['latitude']
        longitude = form.cleaned_data['longitude']

        # Get next week's date
        next_week = timezone.now() + timezone.timedelta(weeks=1)

        # Get Point
        location = Point(latitude, longitude, srid=4326)

        # Look up events
        events = Event.objects.filter(datetime__lte=next_week).annotate(distance=Distance('venue__location', location)).order_by('distance')[0:5]

        # Render the template
        return render_to_response('gigs/lookupresults.html', {
            'events': events
            })

如果我在获取事件后插入断点：

ipdb> from gigs.models import Venue
ipdb> from django.core.serializers import serialize
ipdb> venues = Venue.objects.all()
ipdb> serialize('geojson', venues, geometry_field='location', fields=('name',))
'{"type": "FeatureCollection", "crs": {"type": "name", "properties": {"name": "EPSG:4326"}}, "features": [{"type": "Feature", "geometry": {"type": "Point", "coordinates": [77.13845850820013, 88.27032065635657]}, "properties": {"name": "Venue1"}}, {"type": "Feature", "geometry": {"type": "Point", "coordinates": [-144.48274402224723, -35.87841402981486]}, "properties": {"name": "Venue2"}}, {"type": "Feature", "geometry": {"type": "Point", "coordinates": [15.249714163005194, -39.942840871151624]}, "properties": {"name": "Venue3"}}, {"type": "Feature", "geometry": {"type": "Point", "coordinates": [-63.376261279235095, -6.222101297964656]}, "properties": {"name": "Venue4"}}, {"type": "Feature", "geometry": {"type": "Point", "coordinates": [153.29028611820962, -4.285826286375041]}, "properties": {"name": "Venue5"}}, {"type": "Feature", "geometry": {"type": "Point", "coordinates": [-146.08227004805758, 42.4843671723977]}, "properties": {"name": "Venue6"}}, {"type": "Feature", "geometry": {"type": "Point", "coordinates": [149.6004493621263, 34.740389078323844]}, "properties": {"name": "Venue7"}}, {"type": "Feature", "geometry": {"type": "Point", "coordinates": [-144.38342519084884, -55.55425529324768]}, "properties": {"name": "Venue8"}}, {"type": "Feature", "geometry": {"type": "Point", "coordinates": [83.32120247931198, 48.78215628903402]}, "properties": {"name": "Venue9"}}, {"type": "Feature", "geometry": {"type": "Point", "coordinates": [-28.108531225500826, 35.50271671578547]}, "properties": {"name": "Venue10"}}]}'
ipdb> serialize('geojson', events, geometry_field='venue__location', fields=('name',))
'{"type": "FeatureCollection", "crs": {"type": "name", "properties": {"name": "EPSG:4326"}}, "features": [{"type": "Feature", "geometry": null, "properties": {"name": "Event3"}}, {"type": "Feature", "geometry": null, "properties": {"name": "Event9"}}, {"type": "Feature", "geometry": null, "properties": {"name": "Event10"}}, {"type": "Feature", "geometry": null, "properties": {"name": "Event1"}}, {"type": "Feature", "geometry": null, "properties": {"name": "Event7"}}]}'

我可以获取场地列表的位置，但它似乎无法从 Event 模型中获取场地位置。

知道我哪里出错了吗？

Answer 1

希望这不会来得太晚，但答案是您不需要序列化到 GeoJSON 来呈现到地图中。如果你愿意，你可以使用它，但还有很多其他方法。

例如，您可以创建一个 JSON 数组，其中每个元素都是一个 lat,lng 坐标对，您的 javascript 可以遍历该数组并添加到地图中。

使用 GeoDjango 获取相关位置字段

Get related location field with GeoDjango

python

django

geodjango