Convert to Decimal Degrees

Useful little function and logic to convert to decimal degrees for use with Virtual Earth

private double degreesMinutesSecondsToDecimal(string degminsec)
   {
      //Divide the number of seconds by 60, 28.79 ÷ 60 = 0.5166. 
      //Add the result to the number of minutes, 31 + .47983. 
      //Divide the result by 60, 31.47983 ÷ 60 = 0.52466383. 
      //Now add that to the number degrees, 48 + .52466383. 
      //The result is 48.52466383° 

      double seconds = Double.Parse(degminsec.Substring(degminsec.Length - 4, 4));
      double minutes = Double.Parse(degminsec.Substring(degminsec.Length - 6, 2));
      double degrees = Double.Parse(degminsec.Substring(0, degminsec.Length - 6));

      if (degrees > 0)
      {
          return (((seconds / 100 / 60) + minutes) / 60) + degrees;
      }
      else
      {
          return degrees - (((seconds / 100 / 60) + minutes) / 60);
      }
    }