如何解决如何在后端过滤数据以通过 GeoJSONLayerView 向地图显示地理标签
我只需要在用户选择的国家/地区（按 id_ugms 过滤）显示气象站。但是 geodjango 工具不允许您在后端过滤数据。 GeoJSONLayerView 从表中提取所有数据，我必须在前端的传单中过滤整个列表。表中有很多记录，这就是为什么响应时间很长（显示和过滤需要5分钟以上），或者从服务器完全崩溃。如何进行后端过滤？也许还有其他方法？ 我只是尝试进行选择，并通过 geojsonserializer 序列化数据 - 没有任何效果，传单没有给出输入数据的错误。 技术栈：Postgis、Django、Leaflet。
我的实体有一个模型： 模型.py
class WeatherStation(gismodels.Model):
id_station = models.IntegerField(primary_key=True)
station_index = models.IntegerField(default = None)
name_station_rus = models.CharField(default="",max_length=256)
name_station_en = models.CharField(default="",max_length=256)
id_ugms = models.ForeignKey(Ugms,on_delete=models.CASCADE,default = None)
id_country = models.ForeignKey(Country,default = None)
id_subrf = models.ForeignKey(Subrf,default = None)
latitude = models.CharField(default ="",max_length=256)
longitude = models.CharField(default ="",max_length=256)
geom = gismodels.PointField(default ='POINT EMPTY',srid = 4326)
objects = gismodels.Manager()
height_above_sea = models.CharField(default="",max_length=256)
access_level = models.CharField(default="",max_length=256)
def __unicode__(self):
return self.id_station
urls.py
from django.urls import path
from obsnet import views
from django.views.generic import TemplateView
from django.conf.urls import re_path
from djgeojson.views import GeoJSONLayerView
from obsnet.models import WeatherStation
from obsnet.views import StationGeoJSONLayerView
urlpatterns = [
path('',views.home,name='home'),re_path(r'^filterstation.geojson$',StationGeoJSONLayerView.as_view(),name = 'filterstation'),]
views.py
from django.contrib.gis.geos import Point,Polygon
from obsnet.models import WeatherStation
from obsnet.forms import FilterForm
from datetime import datetime
from django.shortcuts import render
from django.http import HttpRequest
import json
from django.contrib.gis.geos import GEOSGeometry
from django.core.serializers import serialize
from djgeojson.serializers import Serializer as GeoJSONSerializer
from djgeojson.views import GeoJSONLayerView
from django.conf.urls import re_path
from djgeojson.http import HttpGeoJSONResponse
from django.http import HttpResponseRedirect
from django.urls import reverse
def home(request):
"""Renders the home page."""
assert isinstance(request,HttpRequest)
id_s = None
id_fed = None
id_country = None
id_ugms = None
if request.method == 'POST':
form = FilterForm(request.POST)
# check whether it's valid:
if form.is_valid():
id_ugms = form.cleaned_data.get('filter_ugms')
if (id_ugms == '0') :
id_ugms = None
return render(
request,'obsnet/index.html',{
'form' : form,'title' : 'Home Page','year' : datetime.now().year,'id_ugms' : id_ugms,},)
else:
form = FilterForm()
return render(
request,{
'form' : form,)
class StationGeoJSONLayerView(GeoJSONLayerView):
model = WeatherStation
properties = ['name_station_rus','station_index','id_subrf','id_country','id_ugms' ]
def head(self,*args,**kwargs):
response = HttpGeoJSONResponse('')
return response
index.html
{% load leaflet_tags %}
{% load geojson_tags %}
<html>
<head>
{% leaflet_js %}
{% leaflet_css %}
<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/2.0.3/jquery.min.js"></script>
<style>
.filter-map-box{
height: 65%;
width: 20%;
float: left;
position: fixed;
background-color: #ffffff;
top: 5%; /* Расстояние сверху */
left: 5%;
padding: 10px;
-webkit-box-shadow: 5px 5px 15px 5px rgba(0,0.27);
box-shadow: 5px 5px 15px 5px rgba(0,0.27);
z-index: 9999;
}
.map-block{
/*width: 75%;*/
}
.leaflet-container { /* all maps */
width: 100%;
height: 100%;
}
#specialbigmap {
height: 1000px;
}
/* Resize the "display_raw" textbox */
.django-leaflet-raw-textarea {
width: 100%;
}
</style>
</head>
<body>
<div class = "map-block">
{% leaflet_map "main" callback="main_map_init" %}
<script type="text/javascript">
function main_map_init (map,options) {
var ugms = '{{ id_ugms }}';
var suburl = '{% url "filterstation" %}';
// Download GeoJSON via Ajax
$.getJSON(suburl,function (filterstation) {
// Add GeoJSON layer
var fea = filterstation.features;
if (ugms !== 'None')
{
for (i = 0; i < fea.length; i++)
{
var prop = fea[i].properties;
if (prop.id_ugms == ugms)
{
console.log(idfiltr );
L.geoJson(filterstation.features[i]).addTo(map).bindPopup(prop.name_station_rus);
}
}
}
});
map.setMaxBounds([[-90,-180],[90,200]]);
map.options.maxBoundsViscosity = 1.0;
L.tileLayer('http://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png',{
attribution: '© <a rel="nofollow" href="http://osm.org/copyright">OpenStreetMap</a> contributors'
}).addTo(map);
}
</script>
</div>
<div class = "filter-map-box">
<form action="" method="post">
<label for="id_filter_label">Фильтр</label>
{% csrf_token %}
{{ form.as_p }}
<input type="Submit" name="submit" value="Отобразить"/>
</form>
</div>
</body>
</html>
解决方法
我将如何使用 DRF（django rest 框架），更具体地说，djangorestframework-gis 创建一个序列化器来将数据序列化为 geojson，如下所示。
#######在 views.py 上做这些
from .models import WeatherStation
from rest_framework_gis.serializers import GeoFeatureModelSerializer
class WeatherStSerializer(GeoFeatureModelSerializer):
class Meta:
model = WeatherStation
geo_field = geom
fields = ('name_station_rus','station_index','id_subrf','id_country','id_ugms')
在查询集中，您可以在将数据传递给序列化程序之前使用所有后端过滤器方法。 看看DRF-gis
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