EFcore 地图坐标

数据库链接

  optionsBuilder.UseSqlServer(App.Configuration["ConnectionStrings:mssql"], x => x.UseNetTopologySuite());

/// <summary>
/// 经纬度， lng+lat,存的是 WGS 84，腾讯地图是GCJ-02,要转换使用.前台录入是用顺序 lat,lng
/// </summary>
public NetTopologySuite.Geometries.Point Location { get; set; }

SQL查询示例，比如计算所有记录与某一点的距离，并按近到远排序

declare @currentLocation geography
select @currentLocation = geography::STPointFromText('POINT(113.466728 22.272262)', 4326)
select *, Location.STDistance(@currentLocation) as 距离 from [SXKJ_HaoJue].[dbo].[Store]
    where Location.STDistance(@currentLocation) < 1000000000
    order by Location.STDistance(@currentLocation)

efcore

下面的 srid 指定 4326, 指的是 WGS 84，是 GPS 和其他地理系统中使用的标准。
x 表示经度, y 表示纬度,  客户端计算的值(距离,长度等)将是度数;
//var geometryFactory = NtsGeometryServices.Instance.CreateGeometryFactory(srid: 4326);
//var currentLocation = geometryFactory.CreatePoint(-122.121512, 47.6739882);
 var currentLocation = new NetTopologySuite.Geometries.Point(input.Lng, input.Lat) { SRID = 4326 };

var nearestCity = db.Cities.OrderBy(c => c.Location.Distance(currentLocation)) .FirstOrDefault();

图体系GCJ-02与WGS84互转

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Wtl.Extensions 
{
    /// <summary>
    /// 地图体系GCJ-02与WGS84互转
    /// </summary>
    public class CoordinateConverter
    {

        public static double[] WGS84ToGCJ02(double lon, double lat)
        {
            double[] transform = EvilTransform.Transform(lat, lon);
            return new double[] { transform[1], transform[0] };
        }

        public static double[] GCJ02ToWGS84(double lon, double lat)
        {
            double d = 0.0000001;
            double longitude = lon;
            double latitude = lat;
            double[] transform;

            do
            {
                transform = EvilTransform.Transform(latitude, longitude);
                latitude += lat - transform[0];
                longitude += lon - transform[1];
            } while (lon - transform[1] > d || lat - transform[0] > d);

            return new double[] { longitude, latitude };
        }
    }
    class EvilTransform
    {
        private  static    double pi = 3.1415926535897932384626;
        private static double a = 6378245.0;
        private static double ee = 0.00669342162296594323;

        // World Geodetic System ==> Mars Geodetic System
        public static double[] Transform(double wgLat, double wgLon)
        {
            double mgLat = 0;
            double mgLon = 0;
            if (OutOfChina(wgLat, wgLon))
            {
                mgLat = wgLat;
                mgLon = wgLon;
            }
            else
            {
                double dLat = TransformLat(wgLon - 105.0, wgLat - 35.0);
                double dLon = TransformLon(wgLon - 105.0, wgLat - 35.0);
                double radLat = wgLat / 180.0 * pi;
                double magic = Math.Sin(radLat);
                magic = 1 - ee * magic * magic;
                double sqrtMagic = Math.Sqrt(magic);
                dLat = (dLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * pi);
                dLon = (dLon * 180.0) / (a / sqrtMagic * Math.Cos(radLat) * pi);
                mgLat = wgLat + dLat;
                mgLon = wgLon + dLon;
            }
            double[] point = { mgLat, mgLon };
            return point;
        }

        private static bool OutOfChina(double lat, double lon)
        {
            return !InChina(lat, lon);
        }

        private static bool InChina(double lat, double lon)
        {
            try
            {
                int var4 = (int)((lon - 73.0D) / 0.5D);
                int var5 = (int)((lat - 3.5D) / 0.5D);
                if (var5 >= 0 && var5 < 101 && var4 >= 0 && var4 < 124)
                {
                    int var6 = 124 * var5 + var4;
                    char var7 = "0000000000000000000000000000000000000000000000000000000000000000000000000000001000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000110000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000110000000101100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001110101011110000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000011011111111100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000011110111111000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000100011011110000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000111111111000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000111111110000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001101011100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000111001110000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001000100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000011000000100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000101001110000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000011110011000100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000111000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000110000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000111100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000011111000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001111100011100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000111111001100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000111000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000111100000000011100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000011110000000000001011111010000001100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000011111000000000111111111111111100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000011111111100000011111111111111111000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001111111111110111111111111111111111110000000000000000000000000000000000000000000000000000000000000000000000000000000000000001111111111111111111111111111111111111100000000000000000000000000000000000000000000000000000000000000000000000000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                    return var7 == '1';
                }
                else
                {
                    return false;
                }
            }
            catch (Exception ex)
            {
                
                return true;
            }
        }

        private static double TransformLat(double x, double y)
        {
            double ret = -100.0 + 2.0 * x + 3.0 * y + 0.2 * y * y + 0.1 * x * y + 0.2 * Math.Sqrt(Math.Abs(x));
            ret += (20.0 * Math.Sin(6.0 * x * pi) + 20.0 * Math.Sin(2.0 * x * pi)) * 2.0 / 3.0;
            ret += (20.0 * Math.Sin(y * pi) + 40.0 * Math.Sin(y / 3.0 * pi)) * 2.0 / 3.0;
            ret += (160.0 * Math.Sin(y / 12.0 * pi) + 320 * Math.Sin(y * pi / 30.0)) * 2.0 / 3.0;
            return ret;
        }

        private static double TransformLon(double x, double y)
        {
            double ret = 300.0 + x + 2.0 * y + 0.1 * x * x + 0.1 * x * y + 0.1 * Math.Sqrt(Math.Abs(x));
            ret += (20.0 * Math.Sin(6.0 * x * pi) + 20.0 * Math.Sin(2.0 * x * pi)) * 2.0 / 3.0;
            ret += (20.0 * Math.Sin(x * pi) + 40.0 * Math.Sin(x / 3.0 * pi)) * 2.0 / 3.0;
            ret += (150.0 * Math.Sin(x / 12.0 * pi) + 300.0 * Math.Sin(x / 30.0 * pi)) * 2.0 / 3.0;
            return ret;
        }
    }
}