c# 在mongo中查询经纬度范围

#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

double y = 26.0623344427;
double x = 119.2916107177;
double maxDistance = 0.5;//单位：公里（千米）
double earchR = 6378137 / 1000.0;//6378137:地球半径，单位：米
double distance = maxDistance / earchR;

IMongoQuery query = Query.WithinCircle("loc", x, y, distance, true);
IMongoQuery query1 = Query.Near("loc", x, y, distance, true);

var _location = new GeoJsonPoint<GeoJson2DGeographicCoordinates>(new GeoJson2DGeographicCoordinates(x, y));
IMongoQuery query2 = Query.Near("loc", _location, distance, true);

ConcurrentBag<double> bags = new ConcurrentBag<double>();
double totaletime = 0;
int max = 1000;
Parallel.For(0, max, (i) =>
{
    DateTime start = DateTime.Now;
    var finds = table.Find(query1).AsQueryable().ToList();
   
    double etime = (DateTime.Now - start).TotalSeconds;
    bags.Add(etime);
});