C#: 數字經緯度和度分秒經緯度間的轉換

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

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

        #endregion


        #region 方法

        /// <summary>
        /// 數字經緯度和度分秒經緯度轉換 (Digital degree of latitude and longitude and vehicle to latitude and longitude conversion)
        /// </summary>
        /// <param name="digitalLati_Longi">數字經緯度</param>
        /// <return>度分秒經緯度</return>
        static public string ConvertDigitalToDegrees(string digitalLati_Longi)
        {
            double digitalDegree = Convert.ToDouble(digitalLati_Longi);
            return ConvertDigitalToDegrees(digitalDegree);
        }

        /// <summary>
        /// 數字經緯度和度分秒經緯度轉換 (Digital degree of latitude and longitude and vehicle to latitude and longitude conversion)
        /// </summary>
        /// <param name="digitalDegree">數字經緯度</param>
        /// <return>度分秒經緯度</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>
        /// 度分秒經緯度(必須含有'°')和數字經緯度轉換 
        /// </summary>
        /// <param name="digitalDegree">度分秒經緯度</param>
        /// <return>數字經緯度</return>
        static public double ConvertDegreesToDigital(string degrees)
        {
            const double num = 60;
            double digitalDegree = 0.0;
            int d = degrees.IndexOf('°');           //度的符號對應的 Unicode 代碼為：00B0[1]（六十進制），顯示為°。
            if (d < 0)
            {
                return digitalDegree;
            }
            string degree = degrees.Substring(0, d);
            digitalDegree += Convert.ToDouble(degree);

            int m = degrees.IndexOf('′');           //分的符號對應的 Unicode 代碼為：2032[1]（六十進制），顯示為′。
            if (m < 0)
            {
                return digitalDegree;
            }
            string minute = degrees.Substring(d + 1, m - d - 1);
            digitalDegree += ((Convert.ToDouble(minute)) / num);

            int s = degrees.IndexOf('″');           //秒的符號對應的 Unicode 代碼為：2033[1]（六十進制），顯示為″。
            if (s < 0)
            {
                return digitalDegree;
            }
            string second = degrees.Substring(m + 1, s - m - 1);
            digitalDegree += (Convert.ToDouble(second) / (num * num));

            return digitalDegree;
        }


        /// <summary>
        /// 度分秒經緯度(必須含有'/')和數字經緯度轉換 
        /// </summary>
        /// <param name="digitalDegree">度分秒經緯度</param>
        /// <param name="cflag">分隔符</param>
        /// <return>數字經緯度</return>
        static public double ConvertDegreesToDigital_default(string degrees)
        {
            char ch = '/';
            return ConvertDegreesToDigital(degrees, ch);
        }

        /// <summary>
        /// 度分秒經緯度和數字經緯度轉換 
        /// </summary>
        /// <param name="digitalDegree">度分秒經緯度</param>
        /// <param name="cflag">分隔符</param>
        /// <return>數字經緯度</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
    }
}