geojson | 易学教程

find() method in mongodb returns undefined

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问题 I am trying to create a route to retrieve the records with nearby location coordinates. I checked the logs and found the "docs" value as undefined. What am I going wrong with? router.get('/userlist/:lat/:lng', function (req, res) { var db = req.db; var lat = req.params.lat, lng = req.params.lng; console.log("lat "+lat); console.log("lng "+lng); var collection = db.get('userlist'); collection.find({ "location": { $nearSphere: { $geometry: { type: "Point" , coordinates: [ lat , lng ] } } } }, {

Extract the coordinates from the LineStringField

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问题 I've this simple model from GeoDjango for a line vector: from django.contrib.gis.db import models class LineBuffer(models.Model): geom = models.LineStringField() def __int__(self): return self.pk @property def coordinates(self): return str(self.geom.x) + ', ' + str(self.geom.y) I need to create a buffer using Turf.js; the results will be redered using MapBox. With this view I create my map: def line_mapbox_turf_buffer(request): geometry = LineBuffer.objects.all() context = { 'geometry':

mongoose geojson in schema, “Can't extract geo keys” error

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问题 I have a mongodb collection with a defined schema, and I updated this schema to include lat/lon coordinates. old version: var schema = mongoose.Schema({ id: String, name: String, address: String, city: String, zip: String, country: String, phoneNumber: String, mobile: String, website: String, email: String, }); new version var schema = mongoose.Schema({ id: String, name: String, address: String, city: String, zip: String, country: String, phoneNumber: String, mobile: String, website: String,

Select one feature of multiple overlapping features (here polygons) on a Leaflet map

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问题 I have a map with multiple polygons rendered on it which can overlap eachother. I use leafletPip.pointInLayer(point, layer) from https://github.com/mapbox/leaflet-pip for determining which polygons do overlap. This happens in the processClick function. In the Vue object I create the map and my GeoJSON layer with the polygons. What I now want is following feature: if you click on a point on the map and this point is contained in multiple polygons, you have something like a selection tool, e.g.

官方示例（十三）：3步70行代码开发GIS点坐标技术ThingJS

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#前端开发# #三维可视化# #GIS坐标点# 基础图层叠加 ajax开发技术解析三步创建点坐标简介：坐标点是电子地图的常用元素，用于定位、路径规划和位置标识等。三维空间内的坐标点有长度、宽度和高度，并带有GIS地理信息数据，ThingJS推荐使用ajax开发技术等逻辑，轻松创建点坐标。体验见Demo： http://www.thingjs.com/guide/?m=sample 1. 基础图层叠加动态加载地球组件之后，基于Map底图创建瓦片图层、点图层，进行图层叠加，在对象图层ThingLayer进行更灵活的二次开发。开发对象主要是点坐标，图层命名为pointLayer。将渲染后的图片，按照一定的规则结合比例尺切成小的瓦片图形，最后动态加载瓦片以提升网络加载效率，这就是瓦片图层的由来。通过设置相机的飞行视角，修改飞行时间、地理位置、高度等参数，3D地图动效更炫酷！ 2. ajax开发技术解析利用ajax开发技术，在点图层中创建点坐标。ajax函数是一种创建交互式、快速动态网页应用的网页开发技术，保证不过多占用网页资源，只需要对点坐标部分进行更新，即可快速创建动态坐标。具体需要读取Geojason中的坐标及属性来提取数据并渲染图片，示例代码见下方。 3. 三步创建点坐标（1）读取Geojason数据运行代码遍历geojason中的所有数据

Cesium入门1

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Cesium入门1 - Cesium介绍 Cesium中文网： http://cesiumcn.org/ | 国内快速访问： http://cesium.coinidea.com/ Cesium简介 Cesium官网： https://cesiumjs.org 官网中标题写到： An open-source JavaScript library for world-class 3D globes and maps Cesium是一款开源的基于JavaScript的3D地图框架。其实他就是一个地图可视化框架官网中描述写到： CesiumJS is a geospatial 3D mapping platform for creating virtual globes. Our mission is to create the leading web-based globe and map for visualizing dynamic data. We strive for the best possible performance, precision, visual quality, ease of use, platform support, and content. CesiumJS 是一款用于创建虚拟场景的3D地理信息平台。目标是用于创建以基于Web的地图动态数据可视化

How can I flatten a foreignkey object with django-rest-framework-(gis)

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问题 I have searched long and far for a solution that is up to date and specific to my problem but have yet not found a solution or a clear documentation on what I really need to do in order to flatten a relationship to become geojson compliant. This question is almost identical to mine, however the solutions or answers does not solve the problem and still produces invalid GeoJSON. django-rest-framework-gis related field Related Set serializer geo_field as PointField from another model - Django

Spatial Datatype (geometry) to GeoJSON

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问题 I want to convert geom ( geometry ) datatype to GeoJSON. How could I do that? For example, the geometry in WKT: POLYGON((455216.346127297 4288433.28426224,455203.386722146 4288427.76317716,455207.791765017 4288417.51116228,455220.784166744 4288423.30230044,455216.346127297 4288433.28426224)) To the following GeoJSON: { "type": "Polygon", "coordinates": [ [ [100.0, 0.0], [101.0, 0.0], [101.0, 1.0], [100.0, 1.0], [100.0, 0.0] ], [ [100.2, 0.2], [100.8, 0.2], [100.8, 0.8], [100.2, 0.8], [100.2,

Spatial Datatype (geometry) to GeoJSON

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Spatial Datatype (geometry) to GeoJSON

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