79 lines
2.4 KiB
C#
79 lines
2.4 KiB
C#
using System;
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namespace LeanCloud.Storage {
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public class LCGeoPoint {
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/// <summary>
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/// 纬度
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/// </summary>
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public double Latitude {
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get;
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}
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/// <summary>
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/// 经度
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/// </summary>
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public double Longitude {
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get;
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}
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public LCGeoPoint(double latitude, double longtitude) {
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Latitude = latitude;
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Longitude = longtitude;
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}
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public static LCGeoPoint Origin {
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get {
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return new LCGeoPoint(0, 0);
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}
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}
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/// <summary>
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/// 据某点的距离（单位：千米）
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/// </summary>
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/// <param name="point"></param>
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/// <returns></returns>
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public double KilometersTo(LCGeoPoint point) {
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if (point == null) {
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throw new ArgumentNullException(nameof(point));
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}
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return RadiansTo(point) * 6371.0;
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}
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/// <summary>
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/// 据某点的距离（单位：英里）
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/// </summary>
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/// <param name="point"></param>
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/// <returns></returns>
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public double MilesTo(LCGeoPoint point) {
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if (point == null) {
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throw new ArgumentNullException(nameof(point));
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}
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return RadiansTo(point) * 3958.8;
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}
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/// <summary>
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/// 据某点的距离（单位：弧度）
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/// </summary>
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/// <param name="point"></param>
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/// <returns></returns>
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public double RadiansTo(LCGeoPoint point) {
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if (point == null) {
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throw new ArgumentNullException(nameof(point));
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}
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double d2r = Math.PI / 180.0;
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double lat1rad = Latitude * d2r;
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double long1rad = Longitude * d2r;
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double lat2rad = point.Latitude * d2r;
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double long2rad = point.Longitude * d2r;
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double deltaLat = lat1rad - lat2rad;
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double deltaLong = long1rad - long2rad;
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double sinDeltaLatDiv2 = Math.Sin(deltaLat / 2);
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double sinDeltaLongDiv2 = Math.Sin(deltaLong / 2);
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double a = sinDeltaLatDiv2 * sinDeltaLatDiv2 +
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Math.Cos(lat1rad) * Math.Cos(lat2rad) * sinDeltaLongDiv2 * sinDeltaLongDiv2;
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a = Math.Min(1.0, a);
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return 2 * Math.Sin(Math.Sqrt(a));
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}
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}
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}
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