计算两个经纬度之间的距离

/// <summary>
/// 获取两个经纬度之间的距离
/// </summary>
/// <param name="LonA">经度A</param>
/// <param name="LatA">纬度A</param>
/// <param name="LonB">经度B</param>
/// <param name="LatB">经度B</param>
/// <returns>距离（千米）</returns>
public static double getDistance(double LonA, double LatA, double LonB, double LatB)
{
// 东西经，南北纬处理，只在国内可以不处理(假设都是北半球，南半球只有澳洲具有应用意义)
double MLonA = LonA;
double MLatA = LatA;
double MLonB = LonB;
double MLatB = LatB;
// 地球半径（千米）
double R = 6371.004;
double C = Math.Sin(rad(LatA)) * Math.Sin(rad(LatB)) + Math.Cos(rad(LatA)) * Math.Cos(rad(LatB)) * Math.Cos(rad(MLonA - MLonB));
return (R * Math.Acos(C));
}

private static double rad(double d)
{
return d * Math.PI / 180.0;
}