C#: 数字经纬度和度分秒经纬度间的转换

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

namespace ConsoleApplication1
{
    /// <summary>
    /// 公用的特殊函数
    /// </summary>
    public class SpecialFunctions
    {
        #region 构造函数
        /// <summary>
        /// 构造函数
        /// </summary>
        public SpecialFunctions()
        { }

        #endregion


        #region 方法

        /// <summary>
        /// 数字经纬度和度分秒经纬度转换 (Digital degree of latitude and longitude and vehicle to latitude and longitude conversion)
        /// </summary>
        /// <param name="digitalLati_Longi">数字经纬度</param>
        /// <return>度分秒经纬度</return>
        static public string ConvertDigitalToDegrees(string digitalLati_Longi)
        {
            double digitalDegree = Convert.ToDouble(digitalLati_Longi);
            return ConvertDigitalToDegrees(digitalDegree);
        }

        /// <summary>
        /// 数字经纬度和度分秒经纬度转换 (Digital degree of latitude and longitude and vehicle to latitude and longitude conversion)
        /// </summary>
        /// <param name="digitalDegree">数字经纬度</param>
        /// <return>度分秒经纬度</return>
        static public string ConvertDigitalToDegrees(double digitalDegree)
        {
            const double num = 60;
            int degree = (int)digitalDegree;
            double tmp = (digitalDegree - degree) * num;
            int minute = (int)tmp;
            double second = (tmp - minute) * num;
            string degrees = "" + degree + "°" + minute + "′" + second + "″";
            return degrees;
        }


        /// <summary>
        /// 度分秒经纬度(必须含有'°')和数字经纬度转换 
        /// </summary>
        /// <param name="digitalDegree">度分秒经纬度</param>
        /// <return>数字经纬度</return>
        static public double ConvertDegreesToDigital(string degrees)
        {
            const double num = 60;
            double digitalDegree = 0.0;
            int d = degrees.IndexOf('°');           //度的符号对应的 Unicode 代码为：00B0[1]（六十进制），显示为°。
            if (d < 0)
            {
                return digitalDegree;
            }
            string degree = degrees.Substring(0, d);
            digitalDegree += Convert.ToDouble(degree);

            int m = degrees.IndexOf('′');           //分的符号对应的 Unicode 代码为：2032[1]（六十进制），显示为′。
            if (m < 0)
            {
                return digitalDegree;
            }
            string minute = degrees.Substring(d + 1, m - d - 1);
            digitalDegree += ((Convert.ToDouble(minute)) / num);

            int s = degrees.IndexOf('″');           //秒的符号对应的 Unicode 代码为：2033[1]（六十进制），显示为″。
            if (s < 0)
            {
                return digitalDegree;
            }
            string second = degrees.Substring(m + 1, s - m - 1);
            digitalDegree += (Convert.ToDouble(second) / (num * num));

            return digitalDegree;
        }


        /// <summary>
        /// 度分秒经纬度(必须含有'/')和数字经纬度转换 
        /// </summary>
        /// <param name="digitalDegree">度分秒经纬度</param>
        /// <param name="cflag">分隔符</param>
        /// <return>数字经纬度</return>
        static public double ConvertDegreesToDigital_default(string degrees)
        {
            char ch = '/';
            return ConvertDegreesToDigital(degrees, ch);
        }

        /// <summary>
        /// 度分秒经纬度和数字经纬度转换 
        /// </summary>
        /// <param name="digitalDegree">度分秒经纬度</param>
        /// <param name="cflag">分隔符</param>
        /// <return>数字经纬度</return>
        static public double ConvertDegreesToDigital(string degrees, char cflag)
        {
            const double num = 60;
            double digitalDegree = 0.0;
            int d = degrees.IndexOf(cflag);
            if (d < 0)
            {
                return digitalDegree;
            }
            string degree = degrees.Substring(0, d);
            digitalDegree += Convert.ToDouble(degree);

            int m = degrees.IndexOf(cflag, d + 1);
            if (m < 0)
            {
                return digitalDegree;
            }
            string minute = degrees.Substring(d + 1, m - d - 1);
            digitalDegree += ((Convert.ToDouble(minute)) / num);

            int s = degrees.Length;
            if (s < 0)
            {
                return digitalDegree;
            }
            string second = degrees.Substring(m + 1, s - m - 1);
            digitalDegree += (Convert.ToDouble(second) / (num * num));

            return digitalDegree;
        }

        #endregion
    }
}