/// <summary>
/// By Haversine https://en.wikipedia.org/wiki/Haversine_formula
/// </summary>
/// <returns></returns>
public static double GetDistanceByHaversine([NotNull] CoordinateModel origin, [NotNull] CoordinateModel destination, [NotNull] UnitOfLengthModel unitOfLength)
{
var dLat = (destination.Latitude - origin.Latitude) * ElectLocationConstants.DegreesToRadians;
var dLon = (destination.Longitude - origin.Longitude) * ElectLocationConstants.DegreesToRadians;
var a = Math.Pow(Math.Sin(dLat / 2), 2) +
Math.Cos(origin.Latitude * ElectLocationConstants.DegreesToRadians) *
Math.Cos(destination.Latitude * ElectLocationConstants.DegreesToRadians) *
Math.Pow(Math.Sin(dLon / 2), 2);
// central angle, aka arc segment angular distance
var centralAngle = 2 * Math.Atan2(Math.Sqrt(a), Math.Sqrt(1 - a));
var distance = ElectLocationConstants.EarthRadiusMile * centralAngle;
return(unitOfLength.ConvertFromMiles(distance));
}
/// <summary>
/// By Spherical law of cosines http://en.wikipedia.org/wiki/Spherical_law_of_cosines
/// </summary>
public static double GetDistance([NotNull] CoordinateModel origin, [NotNull] CoordinateModel destination, [NotNull] UnitOfLengthModel unitOfLength)
{
var theta = origin.Longitude - destination.Longitude;
var thetaRad = theta * ElectLocationConstants.DegreesToRadians;
var targetRad = destination.Latitude * ElectLocationConstants.DegreesToRadians;
var baseRad = origin.Latitude * ElectLocationConstants.DegreesToRadians;
var distance =
Math.Sin(baseRad) * Math.Sin(targetRad) + Math.Cos(baseRad) *
Math.Cos(targetRad) * Math.Cos(thetaRad);
distance = Math.Acos(distance);
// calculate to earth radius by miles
distance = distance * ElectLocationConstants.EarthRadiusMile;
return(unitOfLength.ConvertFromMiles(distance));
}
/// <summary>
/// By Geographical distance http://en.wikipedia.org/wiki/Geographical_distance
/// </summary>
public static double GetDistanceByGeo([NotNull] CoordinateModel origin, [NotNull] CoordinateModel destination, [NotNull] UnitOfLengthModel unitOfLength)
{
var radLatOrigin = origin.Latitude * ElectLocationConstants.DegreesToRadians;
var radLatDestination = destination.Latitude * ElectLocationConstants.DegreesToRadians;
var dLat = radLatDestination - radLatOrigin;
var dLon = (destination.Longitude - origin.Longitude) * ElectLocationConstants.DegreesToRadians;
var a = dLon * Math.Cos((radLatOrigin + radLatDestination) / 2);
// central angle, aka arc segment angular distance
var centralAngle = Math.Sqrt(a * a + dLat * dLat);
// great-circle (orthodromic) distance on Earth between 2 points
var distance = ElectLocationConstants.EarthRadiusMile * centralAngle;
return(unitOfLength.ConvertFromMiles(distance));
}