九色国产,午夜在线视频,新黄色网址,九九色综合,天天做夜夜做久久做狠狠,天天躁夜夜躁狠狠躁2021a,久久不卡一区二区三区

dlat=p2_lat-p1_lat;
dlon=p2_lon-p1_lon;
a=sin(dlat/2)*sin(dlat/2)+cos(p1_lat)*cos(p2_lat)*sin(dlon/2)*sin(dlon/2);
c=2*asin(min(1,sqrt(a)));
d=R*c;
jcstone 2012年4月12

 

 

 

精度不夠，R的取值是問題

本方法中R為本地卯酉圈半徑N和子午圈半徑M的均值R=sqrt(M*N) 橢球?yàn)閃GS84橢球

精度不及轉(zhuǎn)為空間直角坐標(biāo)系坐標(biāo)距離計(jì)算

 

   
         #region 計(jì)算地理幾何坐標(biāo)點(diǎn)的距離
        /// <summary>
        /// 近似計(jì)算兩大地點(diǎn)的距離
        /// </summary>
        /// <param name="StartLocation"></param>
        /// <param name="EndLocation"></param>
        /// <returns></returns>
         public double MeasureDistance(Location StartLocation, Location EndLocation)
         {
             //double R =6371000;
             double R = new EarthEllipsoid(EarthSphereType.WGS1984).Sphere_LocalRadius(StartLocation);
             return MeasureDistance(StartLocation, EndLocation, R);
         }

        /// <summary>
         /// 近似計(jì)算兩大地點(diǎn)的距離
        /// </summary>
        /// <param name="StartLocation">起點(diǎn)</param>
        /// <param name="EndLocation">止點(diǎn)</param>
        /// <param name="R">本地地球曲率半徑</param>
        /// <returns>距離（米）</returns>
         public double MeasureDistance(Location StartLocation, Location EndLocation,double R)
         {          
             DegreeConvert Degreeconvert = new DegreeConvert();
             double startlat = Degreeconvert.ToRadianByDeg(StartLocation.Latitude);
             double endlat = Degreeconvert.ToRadianByDeg(EndLocation.Latitude);
             double dLat = Degreeconvert.ToRadianByDeg(EndLocation.Latitude - StartLocation.Latitude);
             double dLon = Degreeconvert.ToRadianByDeg(EndLocation.Longitude - StartLocation.Longitude);

             double a = Math.Sin(dLat / 2) * Math.Sin(dLat / 2) +
                 Math.Cos(startlat) * Math.Cos(endlat) *
                 Math.Sin(dLon / 2) * Math.Sin(dLon / 2);
             double c = 2 * Math.Asin(Math.Min(1, Math.Sqrt(a)));
             double d = R * c;
             return d;
         }

      

        /// <summary>
        /// 計(jì)算大地線（地理坐標(biāo)點(diǎn)集合）的距離
        /// </summary>
        /// <param name="locations"></param>
        /// <returns></returns>
         public double MeasureDistance(LocationCollection locations)
         {
             if (locations.Count < 2) return 0;
             Location center = GetCenterLocation(locations[0], locations[locations.Count - 1]);
             //本地地球平均曲率半徑
             double R = new EarthEllipsoid(EarthSphereType.WGS1984).Sphere_LocalRadius(center);
             //double R =6371000;

             double length = 0;
             for (int i = 0; i < locations.Count - 1; i++)
             {
                 length = length + MeasureDistance(locations[i], locations[i + 1],R);
             }
             return length;
           
         }

         #endregion

 

 

 

[0] = {30.4762317584019,114.337461116389,0}

[1] = {30.4772951042471,114.34328687437,0} 

 

采用上述算法近似計(jì)算 = 571.89291808016424

空間直角坐標(biāo)系 571.68532983587249

SQL2008 計(jì)算結(jié)果571.685330473182

 

 DECLARE @g geography;
DECLARE @h geography;
SET @g = geography::STGeomFromText('POINT(114.337461116389 30.4762317584019)', 4326);
SET @h = geography::STGeomFromText('POINT(114.34328687437 30.4772951042471)', 4326);
SELECT @g.STDistance(@h);

 

本站僅提供存儲(chǔ)服務(wù)，所有內(nèi)容均由用戶發(fā)布，如發(fā)現(xiàn)有害或侵權(quán)內(nèi)容，請(qǐng)點(diǎn)擊舉報(bào)。