c# 实现的mongodb空间索引，空间查询(一)

矫情吗；* 2021-11-19 14:26 342阅读 0赞

using MongoDB.Bson;
    using MongoDB.Driver;
    using MongoDB.Driver.Builders;
    using MongoDB.Driver.GeoJsonObjectModel;
    using System;
    using System.Collections.Generic;
    using System.Diagnostics;
    using System.Linq;
    using System.Text;
    using System.Threading.Tasks;
    
    namespace ConsoleApplication1
    {
        // > db.LbsItem.findOne();
        //{
        //        "_id" : ObjectId("5d315dcc4b0142ec4e44f6e5"),
        //        "name" : "Alice-0",
        //        "loc" : {
        //                "type" : "Point",
        //                "coordinates" : [
        //                        158.78458362714602,
        //                        58.53367549904328
        //                 ]
        //                }
        //}
        //>
        class demo001
        {
    
        static string mongodb = "mongodb://127.0.0.1:27017";
        static string database = "2dshpere";
        static string tblName = "LbsItem";
        static MongoCollection<BsonDocument> table;
        public static void Func()
        {
            MongoClient client;
            MongoServer server;
            MongoDatabase db;
            MongoClientSettings setting = new MongoClientSettings();
            setting.MaxConnectionPoolSize = 1000;
            setting.MinConnectionPoolSize = 500;
            client = new MongoClient(mongodb);
    
    
            server = client.GetServer();
            db = server.GetDatabase(database);
            table = db.GetCollection(tblName);
            //InsertRecords(db);
            #region 索引
            //IndexKeysDocument doc = new IndexKeysDocument();//新建索引
            //2d 平面坐标索引，适用于基于平面的坐标计算。也支持球面距离计算，不过官方推荐使用2dsphere索引
            //BsonValue value = BsonValue.Create("2d");//创建2d索引
            //2dsphere 几何球体索引，适用于球面几何运算
            //不过，只要坐标跨度不太大（比如几百几千公里），这两个索引计算出的距离相差几乎可以忽略不计
            //BsonValue value = BsonValue.Create("2dsphere");//创建2d索引
            //doc.Add("loc", value);//loc为数据库中2d索引的对象名称
            //table.CreateIndex(doc);//创建索引
            #endregion
            if (!table.IndexExistsByName("loc_2dsphere"))
            {
                table.CreateIndex(IndexKeys.GeoSpatialSpherical("loc"));
            }
            if (!table.IndexExistsByName("loc.coordinates_2dsphere"))
            {
                table.CreateIndex(IndexKeys.GeoSpatialSpherical("loc.coordinates"));
            }
            double y = 34.7550188169279;
            double x = 93.0100000;
            double maxDistance = 200;//单位公里（千米） 
                                     //6378137：地球半径，单位：米 
                                     //圆形
                                     //IMongoQuery query = Query.WithinCircle("loc", x, y, maxDistance / (6378137 / 1000.0), true);
                                     //最近  弧度true，度false
                                     //IMongoQuery query = Query.Near("loc", x, y, maxDistance / (6378137 / 1000.0), true);
                                     //矩形
            IMongoQuery query = Query.WithinRectangle("loc.coordinates", 118.0, 24.0, 120.0, 30.0);//
            
            //var queryGeo = "{'loc':{$geoWithin:{$box: [[118.0, 24.0],[ 120.0,30.0 ]]}}}";
            //var filter = MongoDB.Bson.Serialization.BsonSerializer.Deserialize<BsonDocument>(queryGeo);
            
            //var result = table.Find(filter.to).ToList();
            //多边形
    
            Stopwatch sw = new Stopwatch();
            sw.Start();
            var finds = table.Find(query).ToList();
    
            long count = finds.Count();
            sw.Stop();
            long ts = sw.ElapsedMilliseconds;
            //foreach (var item in finds)
            //{
            //    Console.WriteLine(item);
            //}
            Console.WriteLine("数量：" + count);
            Console.WriteLine("over耗时：" + ts);
            Console.ReadLine();
        }
    
        /// <summary>
        /// 插入测试数据
        /// </summary>
        /// <param name="database"></param>
        static void InsertRecords(MongoDatabase database)
        {
            MongoCollection<BsonDocument> places = database.GetCollection<BsonDocument>("LbsItem");
            Random rd = new Random();
            List<LbsItem> list = new List<LbsItem>();
            for (int i = 0; i < 500000; i++)
            {
                LbsItem li = new LbsItem();
                li.name = "Alice-" + i;
                li.loc = GeoJson.Point(new GeoJson2DGeographicCoordinates(rd.NextDouble() * 179.0, rd.NextDouble() * 89.0));
                list.Add(li);
            }
    
            places.InsertBatch(list);
        }
    }
    
    
    ///(重要的是要注意数组中的顺序,即经度,纬度 – 遵循x,y的更逻辑顺序,而不是纬度先于经度的更常用形式)：
    public class LbsItem
    {
        ///
        /// <summary> 
        /// 终端标识 
        /// </summary> 
        public string name
        {
            get; set;
        }
        /// <summary> 
        /// 
        /// </summary> 
        public GeoJsonPoint<GeoJson2DGeographicCoordinates> loc { get; set; }
    
    }
    
    }