在给定坐标和最大距离查询结果的情况下，用平均堆栈Mongoose查找与某个点最近的点。
在给定坐标和最大距离查询结果的情况下，用平均堆栈Mongoose查找与某个点最近的点。
提问于 2016-06-09 17:54:42
我有些日子没能解决的问题，甚至看看相关的堆栈溢出Q/A。
我正在开发一个重用Scotch's Create Stack Google Map App教程由Ahmed Haque编写方法的应用程序。
我正在尝试实现一个应用程序，它使用Google 绘制Points、LineStrings和Polygons，这些坐标包含在存储在MongoDB实例中的GeoJson文件中。
我正在使用Mongoose为我的数据构建模式并查询我的MongoDB数据库。
我想找出最近的点，
CP到某个点，P0，给定P0's latitude and longitude，给出一个最大半径，distance，用来找到感兴趣的点。
考虑到图像结束，我想要这样做，例如，如果我插入2000 (公里)，我的查询将找到距P0最大2000公里的所有点。在本例中，它可能会给我P1和P2。
当我的Mongoose Schema中只有点数时，我才能做到这一点。
我有这个Schema ，只有标记(点)
// Pulls Mongoose dependency for creating schemas
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
// Creates a User Schema.
var MarkerSchema = new Schema({
username: {type: String, required: true},
location: {type: [Number], required: true}, // [Long, Lat]
created_at: {type: Date, default: Date.now},
updated_at: {type: Date, default: Date.now}
});
// Indexes this schema in 2dsphere format
MarkerSchema.index({location: '2dsphere'});
module.exports = mongoose.model('mean-markers', MarkerSchema);这是我的Old Query for only Markers**:**
var User = require('./model.js');
app.post('/query/', function(req, res) {
// Grab all of the query parameters from the body.
var lat = req.body.latitude;
var long = req.body.longitude;
var distance = req.body.distance;
var reqVerified = req.body.reqVerified;
// Opens a generic Mongoose Query
var query = User.find({});
// ...include filter by Max Distance (converting miles to meters)
if (distance) {
// Using MongoDB's geospatial querying features
query = query.where('location').near({
center: {
type: 'Point',
coordinates: [long, lat]
},
// Converting meters to miles
maxDistance: distance * 1609.34,
spherical: true
});
}
});它真的很好，我能够得到接近的观点。
然后，我将我的Schema更改为更动态，并支持Polylines and Polygons。
我可以插入和绘制新的点，多边形和多边形，用下面的Schema**:**
var mongoose = require('mongoose');
var GeoJSON = require('geojson');
var Schema = mongoose.Schema;
// Creates a Location Schema.
var LocationSchema = new Schema({
name: {type: String, required: true},
location: {
type: {type : String, required: true},
coordinates : [Schema.Types.Mixed]
},
created_at: {type: Date, default: Date.now},
updated_at: {type: Date, default: Date.now}
});
LocationSchema.index({location: '2dsphere'});
module.exports = mongoose.model('mean-locations', LocationSchema);这是我的Mongoose Query**:**
var GeoObjects = require('./model.js');
app.post('/query/', function(req, res) {
// Grab all of the query parameters from the body.
var lat = req.body.latitude;
var long = req.body.longitude;
var distance = req.body.distance;
var query;
if (distance) {
query = GeoObjects.find({'location.type':'Point'})
.where('location.coordinates').near({
center: {
type: 'Point',
coordinates: [lat, long]
},
// Converting meters to miles
maxDistance: distance * 1609.34,
spherical: true
});
}
// Execute Query and Return the Query Results
query.exec(function(err, users) {
if (err)
res.send(err);
console.log(users);
// If no errors, respond with a JSON of all users that meet the criteria
res.json(users);
});
});console.log(users);给了我undefined.
在我的queryCtrl.js中记录查询结果会给出以下错误消息：
name: "MongoError", message: "error processing query: ns=MeanMapApp.mean-locatio…ed error: unable to find index for $geoNear query", waitedMS: 0, ok: 0, errmsg: "error processing query: ns=MeanMapApp.mean-locatio…ed error: unable to find index for $geoNear query"
与略有差异相同：
app.post('/query/', function(req, res) {
// Grab all of the query parameters from the body.
var lat = req.body.latitude;
var long = req.body.longitude;
var distance = req.body.distance;
console.log(lat,long,distance);
var points = GeoObjects.find({'location.type':'Point'});
var loc = parseFloat(points.location.coordinates);
console.log(JSON.stringify(loc));
if (distance) {
var query = points.near(loc, {
center: {
type: 'Point',
coordinates: [parseFloat(lat), parseFloat(long)]
},
// Converting meters to miles
maxDistance: distance * 1609.34,
spherical: true
});
}
});这是一个标记的例子：
{
"name": "user01",
"location": {
"type":"Point",
"coordinates": [102.0, 0.0]
}
}$near运算符如何与距离和maxDistance:一起工作
MongoDB搜索参数$near及其相关属性maxDistance和球形，以指定我们要覆盖的范围。我们将查询体的距离乘以1609.34，因为我们希望将用户的输入(以英里为单位)转换为MongoDB期望的单位(以米为单位)。
- 为什么我要得到
undefined**?** - 这个问题有可能是由我的架构引起的吗？
- ，我怎样才能解决这个问题？
如果你想得到一些澄清，只需在下面发表评论。
提前谢谢。
回答 2
Stack Overflow用户
回答已采纳
发布于 2016-06-20 18:52:54
我终于解决了这个问题。
本质上，这个问题是由模式引起的，因为2dIndex被引用到了一个错误的字段(type and coordinates)。
我使用以下架构进行了求解
var mongoose = require('mongoose');
var GeoJSON = require('geojson');
var Schema = mongoose.Schema;
var geoObjects = new Schema({
name : {type: String},
type: {
type: String,
enum: [
"Point",
"LineString",
"Polygon"
]
},
coordinates: [Number],
created_at: {type: Date, default: Date.now},
updated_at: {type: Date, default: Date.now}
});
// Sets the created_at parameter equal to the current time
geoObjects.pre('save', function(next){
now = new Date();
this.updated_at = now;
if(!this.created_at) {
this.created_at = now
}
next();
});
geoObjects.index({coordinates: '2dsphere'});
module.exports = mongoose.model('geoObjects', geoObjects);和下面的查询
app.post('/query/', function(req, res) {
// Grab all of the query parameters from the body.
var lat = req.body.latitude;
var long = req.body.longitude;
var distance = req.body.distance;
var query = GeoObjects.find({'type':'Point'});
// ...include filter by Max Distance
if (distance) {
// Using MongoDB's geospatial querying features.
query = query.where('coordinates').near({
center: {
type: 'Point',
coordinates: [lat, long]
},
// Converting meters to miles
maxDistance: distance * 1609.34,
spherical: true
});
}
// Execute Query and Return the Query Results
query.exec(function(err, geoObjects) {
if (err)
res.send(err);
// If no errors, respond with a JSON
res.json(geoObjects);
});
});我希望它能帮到别人！
编辑
我所介绍的模式会给LineStrings和Polygons带来一些问题。
以下是允许使用geoQueries的正确模式
linestring-model.js:
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
// Creates a LineString Schema.
var linestrings = new Schema({
name: {type: String, required : true},
geo : {
type : {type: String,
default: "LineString"},
coordinates : Array
},
created_at: {type: Date, default: Date.now},
updated_at: {type: Date, default: Date.now}
});
// Sets the created_at parameter equal to the current time
linestrings.pre('save', function(next){
now = new Date();
this.updated_at = now;
if(!this.created_at) {
this.created_at = now
}
next();
});
linestrings.index({geo : '2dsphere'});
module.exports = mongoose.model('linestrings', linestrings);polygon-model.js
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
// Creates a Polygon Schema.
var polygons = new Schema({
name: {type: String, required : true},
geo : {
type : {type: String,
default: "Polygon"},
coordinates : Array
},
created_at: {type: Date, default: Date.now},
updated_at: {type: Date, default: Date.now}
});
// Sets the created_at parameter equal to the current time
polygons.pre('save', function(next){
now = new Date();
this.updated_at = now;
if(!this.created_at) {
this.created_at = now
}
next();
});
polygons.index({geo : '2dsphere'});
module.exports = mongoose.model('polygons', polygons);LineString插入
{
"name" : "myLinestring",
"geo" : {
"type" : "LineString",
"coordinates" : [
[
17.811,
12.634
],
[
12.039,
18.962
],
[
15.039,
18.962
],
[
29.039,
18.962
]
]
}
}多边形插入：
{
"name" : "Poly",
"geo" : {
"type" : "Polygon",
"coordinates" : [
[
[25.774, -80.190], [18.466, -66.118],
[32.321, -64.757], [25.774, -80.190]
]
]
}
}Stack Overflow用户
发布于 2016-06-13 14:31:32
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/37733030
复制相关文章
相似问题
腾讯云开发者
