/// <summary>
/// Projects the given coordinates onto the xy-coordinate system.
/// </summary>
/// <param name="coordinate">The geographical coordinates to be projected.</param>
/// <returns>The given coordinates projected onto the xy-coordinate system.</returns>
public Point Project(GeoCoordinate coordinate)
{
const double RadianConversionFactor = Math.PI / 180;
double lat = Math.Max(Math.Min(MaxLatitude, coordinate.Latitude), -MaxLatitude);
double sin = Math.Sin(lat * RadianConversionFactor);
double x = R * coordinate.Longitude * RadianConversionFactor;
double y = R * Math.Log((1 + sin) / (1 - sin)) / 2;
return new Point(x, y);
}
/// <summary>
/// Calculates distance between this and another <see cref="GeoCoordinate"/> value.
/// </summary>
/// <param name="other">Other <see cref="GeoCoordinate"/>.</param>
/// <returns>Distance between two <see cref="GeoCoordinate"/> values.</returns>
public double Distance(GeoCoordinate other)
{
const double RadianConversionFactor = Math.PI / 180.0D;
double r = 6378137;
double lambda1 = Longitude * RadianConversionFactor;
double lambda2 = other.Longitude * RadianConversionFactor;
double phi1 = Latitude * RadianConversionFactor;
double phi2 = other.Latitude * RadianConversionFactor;
double dPhi = phi2 - phi1;
double dLambda = lambda2 - lambda1;
double a = Math.Sin(dPhi / 2) * Math.Sin(dPhi / 2) +
Math.Cos(phi1) * Math.Cos(phi2) *
Math.Sin(dLambda / 2) * Math.Sin(dLambda / 2);
double c = 2 * Math.Atan2(Math.Sqrt(a), Math.Sqrt(1 - a));
return r * c;
}
/// <summary>
/// Translates the given geographical coordinate
/// to a cartesian point at the given zoom level.
/// </summary>
/// <param name="coordinate">The coordinate to be translated.</param>
/// <param name="zoom">The zoom level.</param>
/// <returns>The cartesian point corresponding to the given coordinate.</returns>
public virtual Point Translate(GeoCoordinate coordinate, double zoom)
{
Point projectedPoint = Projection.Project(coordinate);
double scale = Scale(zoom);
return Transformation.Transform(projectedPoint, scale);
}
/// <summary> /// Returns the distance between two geographical coordinates. /// </summary> /// <param name="coordinate1">The first geographical coordinate.</param> /// <param name="coordinate2">The second geographical coordinate.</param> /// <returns>The distance between two geographical coordinates.</returns> public abstract double Distance(GeoCoordinate coordinate1, GeoCoordinate coordinate2);
