Aggregate.geoNear(options: Object): Aggregate

支持端:小程序 2.7.4, 云函数 0.8.1, Web

聚合阶段。将记录按照离给定点从近到远输出。

参数

options: Object

属性 类型 默认值 必填 说明
near GeoPoint GeoJSON Point,用于判断距离的点
spherical true 必填,值为 true
limit number 限制返回记录数
maxDistance number 距离最大值
minDistance number 距离最小值
query Object 要求记录必须同时满足该条件(语法同 where)
distanceMultiplier number 返回时在距离上乘以该数字
distanceField string 存放距离的输出字段名,可以用点表示法表示一个嵌套字段
includeLocs string 列出要用于距离计算的字段,如果记录中有多个字段都是地理位置时有用
key string 选择要用的地理位置索引。如果集合由多个地理位置索引,则必须指定一个,指定的方式是指定对应的字段

返回值

Aggregate

API 说明

  • geoNear 必须为第一个聚合阶段
  • 必须有地理位置索引。如果有多个,必须用 key 参数指定要使用的索引。

示例

假设集合 attractions 有如下记录:

{
  "_id": "geoNear.0",
  "city": "Guangzhou",
  "docType": "geoNear",
  "location": {
    "type": "Point",
    "coordinates": [
      113.30593,
      23.1361155
    ]
  },
  "name": "Canton Tower"
},
{
  "_id": "geoNear.1",
  "city": "Guangzhou",
  "docType": "geoNear",
  "location": {
    "type": "Point",
    "coordinates": [
      113.306789,
      23.1564721
    ]
  },
  "name": "Baiyun Mountain"
},
{
  "_id": "geoNear.2",
  "city": "Beijing",
  "docType": "geoNear",
  "location": {
    "type": "Point",
    "coordinates": [
      116.3949659,
      39.9163447
    ]
  },
  "name": "The Palace Museum"
},
{
  "_id": "geoNear.3",
  "city": "Beijing",
  "docType": "geoNear",
  "location": {
    "type": "Point",
    "coordinates": [
      116.2328567,
      40.242373
    ]
  },
  "name": "Great Wall"
}
const $ = db.command.aggregate
db.collection('attractions').aggregate()
  .geoNear({
    distanceField: 'distance', // 输出的每个记录中 distance 即是与给定点的距离
    spherical: true,
    near: db.Geo.Point(113.3089506, 23.0968251),
    query: {
      docType: 'geoNear',
    },
    key: 'location', // 若只有 location 一个地理位置索引的字段,则不需填
    includeLocs: 'location', // 若只有 location 一个是地理位置,则不需填
  })
  .end()

返回结果如下:

{
  "_id": "geoNear.0",
  "location": {
    "type": "Point",
    "coordinates": [
      113.30593,
      23.1361155
    ]
  },
  "docType": "geoNear",
  "name": "Canton Tower",
  "city": "Guangzhou",
  "distance": 4384.68131486958
},
{
  "_id": "geoNear.1",
  "city": "Guangzhou",
  "location": {
    "type": "Point",
    "coordinates": [
      113.306789,
      23.1564721
    ]
  },
  "docType": "geoNear",
  "name": "Baiyun Mountain",
  "distance": 6643.521654040738
},
{
  "_id": "geoNear.2",
  "docType": "geoNear",
  "name": "The Palace Museum",
  "city": "Beijing",
  "location": {
    "coordinates": [
      116.3949659,
      39.9163447
    ],
    "type": "Point"
  },
  "distance": 1894750.4414538583
},
{
  "_id": "geoNear.3",
  "docType": "geoNear",
  "name": "Great Wall",
  "city": "Beijing",
  "location": {
    "type": "Point",
    "coordinates": [
      116.2328567,
      40.242373
    ]
  },
  "distance": 1928300.3308822548
}