数据

Question

对此我感到很麻烦。我正在构建一个小API，以在给定特定坐标的情况下获取最接近的存储元素（在mlab MongoDB中）。

我想使用$ goear之类的Mongo自定义查询工具从数据库中获取最接近的元素。

您可以找到原始存储库here！

数据

原始数据是我转换为geojson格式的.csv小文件。

以下是该.csv的简短版本：

这是它的geojson版本：

{
  "type": "FeatureCollection",
  "features": [
    {
      "type": "Feature",
      "geometry": {
        "type": "Point",
        "coordinates": [2.4049238868200975, 48.82094216189432]
      },
      "properties": {
        "event_type": "imp"
      }
    },
    {
      "type": "Feature",
      "geometry": {
        "type": "Point",
        "coordinates": [2.3645320381923534, 48.816341825787724]
      },
      "properties": {
        "event_type": "imp"
      }
    },
    {
      "type": "Feature",
      "geometry": {
        "type": "Point",
        "coordinates": [2.3274838513968072, 48.86982967859056]
      },
      "properties": {
        "event_type": "imp"
      }
    },
    {
      "type": "Feature",
      "geometry": {
        "type": "Point",
        "coordinates": [2.23284629237154, 48.89111120713999]
      },
      "properties": {
        "event_type": "imp"
      }
    },
    {
      "type": "Feature",
      "geometry": {
        "type": "Point",
        "coordinates": [2.23284629237154, 48.89111120713999]
      },
      "properties": {
        "event_type": "click"
      }
    },
    {
      "type": "Feature",
      "geometry": {
        "type": "Point",
        "coordinates": [2.4204737962258305, 48.85038737901075]
      },
      "properties": {
        "event_type": "imp"
      }
    },
    {
      "type": "Feature",
      "geometry": {
        "type": "Point",
        "coordinates": [2.4214870126092594, 48.86339618816508]
      },
      "properties": {
        "event_type": "imp"
      }
    },
    {
      "type": "Feature",
      "geometry": {
        "type": "Point",
        "coordinates": [2.4144620076022436, 48.876530301936576]
      },
      "properties": {
        "event_type": "imp"
      }
    },
    {
      "type": "Feature",
      "geometry": {
        "type": "Point",
        "coordinates": [2.2470618097659285, 48.88845096504584]
      },
      "properties": {
        "event_type": "imp"
      }
    }
  ]
}

模型

以下是使用猫鼬的架构（如您所见，我确实添加了2dsphere索引）：

const mongoose = require("mongoose");

const FeatureSchema = new mongoose.Schema({
  type: String,
  geometry: {
    type: { type: String, default: "Point" },
    coordinates: { type: [Number] }
  },
  properties: { event_type: String }
});

FeatureSchema.index({ geometry: "2dsphere" });
const MapEventSchema = new mongoose.Schema({
  type: String,
  features: [FeatureSchema]
});

const MapEvent = mongoose.model("mapEvent", MapEventSchema);

module.exports = MapEvent;

测试

这是我正在努力的（与摩卡咖啡有关的）测试：

const assert = require("assert");
const MapEvent = require("../src/models/mapEvents");
const fs = require("fs");

describe("Read test", () => {
  // create new room collection because collection is drop between each file
  beforeEach(done => {
    rawJSON = fs.readFileSync("./src/assets/test_assets/read_test.json");
    const parsedContent = JSON.parse(rawJSON);
    const mapEvent = new MapEvent(parsedContent);
    mapEvent
      .save()
      .then(() => {
        done();
      })
      .catch(error => {
        console.error(error);
      });
  });

  it("Find nearest event by coordonates", done => {
    const distance = 1000;
    const lat = 48.86;
    const lon = 2.35;

    function waitForIndex() {
      return new Promise((resolve, reject) => {
        MapEvent.on("index", error => (error ? reject(error) : resolve()));
      });
    }

    MapEvent.findOne({
      geometry: {
        $near: [lat, lon],
        $maxDistance: distance
      }
    })
      //.then(waitForIndex)
      .then(MapEvent.init())
      .then(nearestResult => {
        console.log("------------");
        console.log(nearestResult);
        console.log("------E-----");
        assert(nearestResult);
        done();
      })
      .catch(error => {
        console.error("************");
        console.error(error);
        console.error("******E*****");
      });
  });
});

输出

您可能会注意到，我注释掉waitForIndex（）（在一个相关的Stackoverflow问题上找到）以改用MapEvent.init（）（在github上找到）。不幸的是，两种解决方案都给我相同的错误输出。

Connection is established
  Create test
(node:12483) DeprecationWarning: collection.ensureIndex is deprecated. Use createIndexes instead.
    ✓ MapEvent saving

  Read test
************
{ MongoError: error processing query: ns=babylon_ad_db.mapevents batchSize=1 limit=1Tree: GEONEAR  field=geometry maxdist=1000 isNearSphere=0
Sort: {}
Proj: {}
 planner returned error: unable to find index for $geoNear query
    at queryCallback (/home/geoffrey/babylon-ad/node_modules/mongodb-core/lib/cursor.js:248:25)
    at /home/geoffrey/babylon-ad/node_modules/mongodb-core/lib/connection/pool.js:532:18
    at process._tickCallback (internal/process/next_tick.js:61:11)
  ok: 0,
  errmsg:
   'error processing query: ns=babylon_ad_db.mapevents batchSize=1 limit=1Tree: GEONEAR  field=geometry maxdist=1000 isNearSphere=0\nSort: {}\nProj: {}\n planner returned error: unable to find index for $geoNear query',
  code: 2,
  codeName: 'BadValue',
  operationTime:
   Timestamp { _bsontype: 'Timestamp', low_: 7, high_: 1536667477 },
  '$clusterTime':
   { clusterTime:
      Timestamp { _bsontype: 'Timestamp', low_: 7, high_: 1536667477 },
     signature: { hash: [Binary], keyId: [Long] } },
  name: 'MongoError',
  [Symbol(mongoErrorContextSymbol)]: {} }
******E*****
    1) Find nearest event by coordonates


  1 passing (3s)
  1 failing

  1) Read test
       Find nearest event by coordonates:
     Error: Timeout of 2000ms exceeded. For async tests and hooks, ensure "done()" is called; if returning a Promise, ensure it resolves. (/home/geoffrey/babylon-ad/test/read_test.js)

我已经进行了一些谷歌搜索，这就是我听说$ near和2dsphere索引的方式。但是，我仍然无法弄清为什么它说找不到索引。即使我用waitForIndex（）或MapEvent.init（）等待它。

这个社区创造了一些很棒的奇迹，希望您能为我提供帮助。

谢谢

Answer 1

这种类型的错误表示未创建索引。通常这是由于无效的坐标数据造成的。也许加载您的mongo shell并确保您的索引存在：

mongo
use yourdatabasename
db.yourcollection.getIndexes()

您应该以类似以下内容结束

{
    "v" : 2,
    "key" : {
      "geometry" : "2dsphere"
    },
    "name" : "geometry_2dsphere",
    "ns" : "databasename.yourcollection",
    "2dsphereIndexVersion" : 3
  }

如果不存在，请尝试在外壳中创建索引-如果无法创建索引，它将引发错误：

db.yourcollection.createIndex( { geometry : "2dsphere" } )

$ near错误-计划人员返回错误：找不到$ geoNear查询的索引

数据

模型

测试

输出

1 个答案: