78 lines
3.0 KiB
C#
78 lines
3.0 KiB
C#
using System;
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using System.Collections.Generic;
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using System.Linq;
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using System.Text;
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namespace ZWL.Common
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{
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public static class DistanceHelper
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{
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/// <summary>
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/// 根据一个给定经纬度的点和距离，进行附近地点查询
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/// </summary>
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/// <param name="longitude">经度</param>
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/// <param name="latitude">纬度</param>
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/// <param name="distance">距离（单位：公里或千米）</param>
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/// <returns>返回一个范围的4个点，最小纬度和纬度，最大经度和纬度</returns>
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public static Boolean FindNeighPosition(double yhJd,double hyWd,double longitude, double latitude, double distance)
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{
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//先计算查询点的经纬度范围
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double r = 6378.137;//地球半径千米
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double dis = distance;//千米距离
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double dlng = 2 * Math.Asin(Math.Sin(dis / (2 * r)) / Math.Cos(latitude * Math.PI / 180));
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dlng = dlng * 180 / Math.PI;//角度转为弧度
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double dlat = dis / r;
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dlat = dlat * 180 / Math.PI;
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double minlat = latitude - dlat;
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double maxlat = latitude + dlat;
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double minlng = longitude - dlng;
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double maxlng = longitude + dlng;
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/*new PositionModel
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{
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MinLat = minlat,
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MaxLat = maxlat,
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MinLng = minlng,
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MaxLng = maxlng
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};*/
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if (minlng < yhJd && yhJd < maxlng && minlat < hyWd && hyWd < maxlat)
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{
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return true;
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}
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return false;
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}
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/// <summary>
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/// 计算两点位置的距离，返回两点的距离，单位：公里或千米
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/// 该公式为GOOGLE提供，误差小于0.2米
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/// </summary>
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/// <param name="lat1">第一点纬度</param>
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/// <param name="lng1">第一点经度</param>
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/// <param name="lat2">第二点纬度</param>
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/// <param name="lng2">第二点经度</param>
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/// <returns>返回两点的距离，单位：公里或千米</returns>
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public static double GetDistance(double lat1, double lng1, double lat2, double lng2)
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{
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//地球半径，单位米
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double EARTH_RADIUS = 6378137;
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double radLat1 = Rad(lat1);
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double radLng1 = Rad(lng1);
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double radLat2 = Rad(lat2);
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double radLng2 = Rad(lng2);
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double a = radLat1 - radLat2;
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double b = radLng1 - radLng2;
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double result = 2 * Math.Asin(Math.Sqrt(Math.Pow(Math.Sin(a / 2), 2) + Math.Cos(radLat1) * Math.Cos(radLat2) * Math.Pow(Math.Sin(b / 2), 2))) * EARTH_RADIUS;
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return result / 1000;
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}
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/// <summary>
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/// 经纬度转化成弧度
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/// </summary>
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/// <param name="d"></param>
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/// <returns></returns>
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private static double Rad(double d)
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{
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return (double)d * Math.PI / 180d;
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}
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}
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}
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