/// <summary>
/// Calculates distance/bearing between two geographic locations on Rhumb line (loxodrome)
/// </summary>
/// <param name="origin">origin location in geographic degrees</param>
/// <param name="destination">destination location in geographic degrees</param>
/// <param name="radius">radius of a geographic sphere, in kilometers</param>
/// <remarks>radius defaults to Earth's mean radius</remarks>
public static GeoRhumb GetRhumb(GeoPoint origin, GeoPoint destination, double radius = GeoGlobal.Earths.Radius)
{
origin = origin.ToRadians();
destination = destination.ToRadians();
var dLat = (destination.Latitude - origin.Latitude);
var dLon = (destination.Longitude - origin.Longitude);
var tDestination = Math.Tan(Math.PI / 4 + destination.Latitude / 2);
var tOrigin = Math.Tan(Math.PI / 4 + origin.Latitude / 2);
var dPhi = Math.Log(tDestination / tOrigin); // E-W line gives dPhi=0
var q = (IsFinite(dLat / dPhi)) ? dLat / dPhi : Math.Cos(origin.Latitude);
// if dLon over 180° take shorter Rhumb across anti-meridian:
if (Math.Abs(dLon) > Math.PI)
{
dLon = dLon > 0 ? -(2 * Math.PI - dLon) : (2 * Math.PI + dLon);
}
var distance = Math.Sqrt(dLat * dLat + q * q * dLon * dLon) * radius;
var bearing = Math.Atan2(dLon, dPhi);
return(new GeoRhumb {
Distance = distance, Bearing = bearing.ToDegreesNormalized()
});
}
private static void GetSphereUv(Vec3 p_point, ref HitRecord p_hitRecord)
{
var phi = Math.Atan2(p_point.Z, p_point.X);
var theta = Math.Asin(p_point.Y);
p_hitRecord.U = 1 - (phi + Math.PI) / (2 * Math.PI);
p_hitRecord.V = (theta + Math.PI / 2) / Math.PI;
}
/// <summary>
/// Returns the counterclock angle between two vectors (between 0 and 2*pi)
/// NOTE: A unique counter clockwise angle really only makes sense onces you've picked a plane normal direction.
/// So as coded, this function is really only intended to be used with 2D vector inputs.
/// </summary>
public static double AngleToCounterClock(Vector3D v1, Vector3D v2)
{
double angle = Math.Atan2(v2.Y, v2.X) - Math.Atan2(v1.Y, v1.X);
if (angle < 0)
{
return(angle + 2 * Math.PI);
}
return(angle);
}
/// <summary>
/// Calculates angle bearing from origin location towards destination location, in degrees
/// <para> North = 0, East = 90, South = 180, West = 270 </para>
/// </summary>
/// <param name="origin">origin location in geographic degrees</param>
/// <param name="destination">destination location in geographic degrees</param>
public static double GetBearingAppx(IGeoLocatable origin, IGeoLocatable destination)
{
// from flight watcher app (not accurate)
var dLat = destination.Latitude - origin.Latitude;
var dLon = destination.Longitude - origin.Longitude;
var angle = Math.Atan2((dLat), (dLon)) * 180.0 / Math.PI;
return(-1 * angle);
//return angle;
}
/// <summary>
/// Calculates the initial bearing from origin location in direction of destination location, in degrees from true North
/// <para> North = 0, East = 90, South = 180, West = 270 </para>
/// </summary>
/// <param name="origin">origin location in geographic degrees</param>
/// <param name="destination">destination location in geographic degrees</param>
public static double GetBearing(IGeoLocatable origin, IGeoLocatable destination)
{
origin = origin.ToRadians();
destination = destination.ToRadians();
var dLat = (destination.Latitude - origin.Latitude);
var dLon = (destination.Longitude - origin.Longitude);
var y = Math.Sin(dLon) * Math.Cos(destination.Latitude);
var x = Math.Cos(origin.Latitude) * Math.Sin(destination.Latitude) -
Math.Sin(origin.Latitude) * Math.Cos(destination.Latitude) * Math.Cos(dLon);
var angle = Math.Atan2(y, x);
return(angle.ToDegreesNormalized());
}
} //NormalizeArray
static void convertToAmplitudePhase(double[,] result)
{
int longIndexBound = result.GetUpperBound(1);
for (var index = 0; index < longIndexBound; ++index)
{
double re = result[0, index];
double im = result[1, index];
double absValue = Math.Round(Math.Sqrt(re * re + im * im) * 100);
double phase = Math.Round(Math.Atan2(re, im) * 180 / Math.PI);
result[0, index] = absValue;
result[1, index] = phase;
} //loop
} //convertToAmplitudePhase
/// <summary>
/// Calculates mid point between two geographic locations on the Great Circle
/// <para>Using the Spherical law of cosines </para>
/// </summary>
/// <param name="origin">origin location in geographic degrees</param>
/// <param name="destination">destination location in geographic degrees</param>
public static GeoPoint GetMidpoint(IGeoLocatable origin, IGeoLocatable destination)
{
origin = origin.ToRadians();
destination = destination.ToRadians();
var dLat = (destination.Latitude - origin.Latitude);
var dLon = (destination.Longitude - origin.Longitude);
var bx = Math.Cos(destination.Latitude) * Math.Cos(dLon);
var by = Math.Cos(destination.Latitude) * Math.Sin(dLon);
var lat = Math.Atan2(Math.Sin(origin.Latitude) + Math.Sin(destination.Latitude),
Math.Sqrt((Math.Cos(origin.Latitude) + bx) * (Math.Cos(origin.Latitude) + bx) + by * by));
var lon = origin.Longitude + Math.Atan2(by, Math.Cos(origin.Latitude) + bx);
lon = (lon + 3 * Math.PI) % (2 * Math.PI) - Math.PI; // normalize to -180..+180º
return(new GeoPoint(lon.ToDegrees(), lat.ToDegrees()));
}
/// <summary>
/// Calculates distance between two geographic locations on the Great Circle
/// <para>Using the Haversine formula</para>
/// <remarks>"Virtues of the Haversine" by R. W. Sinnott, Sky and Telescope, vol 68, no 2, 1984</remarks>
/// </summary>
/// <param name="origin">origin location in geographic degrees</param>
/// <param name="destination">destination location in geographic degrees</param>
/// <param name="radius">radius of a geographic sphere, in kilometers</param>
/// <remarks>radius defaults to Earth's mean radius</remarks>
public static GeoDistance GetDistanceH(IGeoLocatable origin, IGeoLocatable destination, double radius = GeoGlobal.Earths.Radius)
{
origin = origin.ToRadians();
destination = destination.ToRadians();
var dLat = (destination.Latitude - origin.Latitude);
var dLon = (destination.Longitude - origin.Longitude);
var a = Math.Sin(dLat / 2) * Math.Sin(dLat / 2) +
Math.Sin(dLon / 2) * Math.Sin(dLon / 2) *
Math.Cos(origin.Latitude) * Math.Cos(destination.Latitude);
var c = 2 * Math.Atan2(Math.Sqrt(a), Math.Sqrt(1 - a));
var distance = radius * c;
return(new GeoDistance {
Kilometers = distance
});
}
/// <summary>
/// Calculates the destination location at distance and in direction of bearing from origin location
/// <para>Using the Spherical law of cosines </para>
/// </summary>
/// <param name="origin">location in geographic degrees </param>
/// <param name="bearing">bearing in geographic degrees from origin</param>
/// <param name="distance">distance in km</param>
/// <param name="radius">radius in km</param>
/// <remarks>radius defaults to Earth's mean radius</remarks>
public static GeoPoint GetDestination(IGeoLocatable origin, double bearing, double distance, double radius = GeoGlobal.Earths.Radius)
{
origin = origin.ToRadians();
bearing = bearing.ToRadians();
distance = distance / radius; // angular distance in radians
var latitude = Math.Asin(Math.Sin(origin.Latitude) * Math.Cos(distance) +
Math.Cos(origin.Latitude) * Math.Sin(distance) * Math.Cos(bearing));
var x = Math.Sin(bearing) * Math.Sin(distance) * Math.Cos(origin.Latitude);
var y = Math.Cos(distance) - Math.Sin(origin.Latitude) * Math.Sin(origin.Latitude);
var longitude = origin.Longitude + Math.Atan2(x, y);
longitude = (longitude + 3 * Math.PI) % (2 * Math.PI) - Math.PI; // normalize to -180..+180º
var destination = new GeoPoint(longitude.ToDegrees(), latitude.ToDegrees());
return(destination);
}
public static Sphere[] Mirrors(int p, int q, int r, ref Vector3D cellCenter, bool moveToBall = true, double scaling = -1)
{
Geometry g = Util.GetGeometry(p, q, r);
if (g == Geometry.Spherical)
{
// These are in the ball model.
Sphere[] result = SimplexCalcs.MirrorsSpherical(p, q, r);
return(result);
}
else if (g == Geometry.Euclidean)
{
return(SimplexCalcs.MirrorsEuclidean());
}
// This is a rotation we'll apply to the mirrors at the end.
// This is to try to make our image outputs have vertical bi-lateral symmetry and the most consistent in all cases.
// NOTE: + is CW, not CCW. (Because the way I did things, our images have been reflected vertically, and I'm too lazy to go change this.)
double rotation = Math.PI / 2;
// Some construction points we need.
Vector3D p1, p2, p3;
Segment seg = null;
TilePoints(p, q, out p1, out p2, out p3, out seg);
//
// Construct in UHS
//
Geometry cellGeometry = Geometry2D.GetGeometry(p, q);
Vector3D center = new Vector3D();
double radius = 0;
if (cellGeometry == Geometry.Spherical)
{
// Finite or Infinite r
// Spherical trig
double halfSide = Geometry2D.GetTrianglePSide(q, p);
double mag = Math.Sin(halfSide) / Math.Cos(Util.PiOverNSafe(r));
mag = Math.Asin(mag);
// e.g. 43j
//mag *= 0.95;
// Move mag to p1.
mag = Spherical2D.s2eNorm(mag);
H3Models.Ball.DupinCyclideSphere(p1, mag, Geometry.Spherical, out center, out radius);
}
else if (cellGeometry == Geometry.Euclidean)
{
center = p1;
radius = p1.Dist(p2) / Math.Cos(Util.PiOverNSafe(r));
}
else if (cellGeometry == Geometry.Hyperbolic)
{
if (Infinite(p) && Infinite(q) && FiniteOrInfinite(r))
{
//double iiiCellRadius = 2 - Math.Sqrt( 2 );
//Circle3D iiiCircle = new Circle3D() { Center = new Vector3D( 1 - iiiCellRadius, 0, 0 ), Radius = iiiCellRadius };
//radius = iiiCellRadius; // infinite r
//center = new Vector3D( 1 - radius, 0, 0 );
// For finite r, it was easier to calculate cell facet in a more symmetric position,
// then move into position with the other mirrors via a Mobius transformation.
double rTemp = 1 / (Math.Cos(Util.PiOverNSafe(r)) + 1);
Mobius m = new Mobius();
m.Isometry(Geometry.Hyperbolic, -Math.PI / 4, new Vector3D(0, Math.Sqrt(2) - 1));
Vector3D c1 = m.Apply(new Vector3D(1 - 2 * rTemp, 0, 0));
Vector3D c2 = c1;
c2.Y *= -1;
Vector3D c3 = new Vector3D(1, 0);
Circle3D c = new Circle3D(c1, c2, c3);
radius = c.Radius;
center = c.Center;
}
else if (Infinite(p) && Finite(q) && FiniteOrInfinite(r))
{
// http://www.wolframalpha.com/input/?i=r%2Bx+%3D+1%2C+sin%28pi%2Fp%29+%3D+r%2Fx%2C+solve+for+r
// radius = 2 * Math.Sqrt( 3 ) - 3; // Appolonian gasket wiki page
//radius = Math.Sin( Math.PI / q ) / ( Math.Sin( Math.PI / q ) + 1 );
//center = new Vector3D( 1 - radius, 0, 0 );
// For finite r, it was easier to calculate cell facet in a more symmetric position,
// then move into position with the other mirrors via a Mobius transformation.
double rTemp = 1 / (Math.Cos(Util.PiOverNSafe(r)) + 1);
Mobius m = new Mobius();
m.Isometry(Geometry.Hyperbolic, 0, p2);
Vector3D findingAngle = m.Inverse().Apply(new Vector3D(1, 0));
double angle = Math.Atan2(findingAngle.Y, findingAngle.X);
m.Isometry(Geometry.Hyperbolic, angle, p2);
Vector3D c1 = m.Apply(new Vector3D(1 - 2 * rTemp, 0, 0));
Vector3D c2 = c1;
c2.Y *= -1;
Vector3D c3 = new Vector3D(1, 0);
Circle3D c = new Circle3D(c1, c2, c3);
radius = c.Radius;
center = c.Center;
}
else if (Finite(p) && Infinite(q) && FiniteOrInfinite(r))
{
radius = p2.Abs(); // infinite r
radius = DonHatch.asinh(Math.Sinh(DonHatch.e2hNorm(p2.Abs())) / Math.Cos(Util.PiOverNSafe(r))); // hyperbolic trig
// 4j3
//m_jOffset = radius * 0.02;
//radius += m_jOffset ;
radius = DonHatch.h2eNorm(radius);
center = new Vector3D();
rotation *= -1;
}
else if (/*Finite( p ) &&*/ Finite(q))
{
// Infinite r
//double mag = Geometry2D.GetTrianglePSide( q, p );
// Finite or Infinite r
double halfSide = Geometry2D.GetTrianglePSide(q, p);
double mag = DonHatch.asinh(Math.Sinh(halfSide) / Math.Cos(Util.PiOverNSafe(r))); // hyperbolic trig
H3Models.Ball.DupinCyclideSphere(p1, DonHatch.h2eNorm(mag), out center, out radius);
}
else
{
throw new System.NotImplementedException();
}
}
Sphere cellBoundary = new Sphere()
{
Center = center,
Radius = radius
};
Sphere[] interior = InteriorMirrors(p, q);
Sphere[] surfaces = new Sphere[] { cellBoundary, interior[0], interior[1], interior[2] };
// Apply rotations.
bool applyRotations = true;
if (applyRotations)
{
foreach (Sphere s in surfaces)
{
RotateSphere(s, rotation);
}
p1.RotateXY(rotation);
}
// Apply scaling
bool applyScaling = scaling != -1;
if (applyScaling)
{
//double scale = 1.0/0.34390660467269524;
//scale = 0.58643550768408892;
foreach (Sphere s in surfaces)
{
Sphere.ScaleSphere(s, scaling);
}
}
bool facetCentered = false;
if (facetCentered)
{
PrepForFacetCentering(p, q, surfaces, ref cellCenter);
}
// Move to ball if needed.
if (moveToBall)
{
surfaces = MoveToBall(surfaces, ref cellCenter);
}
return(surfaces);
}
public static float PointDirection(Vector2 p0, Vector2 p1)
{
return((float)SMath.Atan2(p1.Y - p0.Y, p1.X - p0.X));
}
public static double GetAngle(Point center, Point endPoint)
{
return(M.Atan2(endPoint.Y - center.Y, endPoint.X - center.X) + PI);
}
/// <summary>
///
/// </summary>
/// <returns></returns>
public float ToHeading()
{
return((float)((Maths.Atan2(X, -Y) + Maths.PI) * (180.0 / Maths.PI)));
}
public static float GetAngle(this Vec2 v)
{
return((float)Math.Atan2(v.Y, v.X));
}
/// <summary>
///
/// </summary>
/// <param name="from"></param>
/// <param name="to"></param>
/// <returns></returns>
public static float SignedAngle(Vector2 from, Vector2 to)
{
return((float)((Maths.Atan2(to.Y, to.X) - Maths.Atan2(from.Y, from.X)) * (180.0 / Maths.PI)));
}
public static float Angle(this Vector2f value)
{
return((float)Math.Atan2(value.Y, value.X));
}
/// <summary>
/// Calculates intersection point of paths from two geographic locations
/// </summary>
/// <param name="origin1">origin of first location in geographic degrees</param>
/// <param name="origin2">origin of second location in geographic degrees</param>
/// <param name="bearing1">bearing from first location in geographic degrees</param>
/// <param name="bearing2">bearing from second location in geographic degrees</param>
/// <param name="radius">radius of a geographic sphere, in kilometers</param>
/// <remarks>radius defaults to Earth's mean radius</remarks>
public static GeoPoint GetIntersection(
IGeoLocatable origin1, double bearing1,
IGeoLocatable origin2, double bearing2, double radius = GeoGlobal.Earths.Radius)
{
origin1 = origin1.ToRadians();
origin2 = origin2.ToRadians();
var brng13 = bearing1.ToRadians();
var brng23 = bearing2.ToRadians();
var dLat = (origin2.Latitude - origin1.Latitude);
var dLon = (origin2.Longitude - origin1.Longitude);
var dist12 = 2 * Math.Asin(Math.Sqrt(Math.Sin(dLat / 2) * Math.Sin(dLat / 2) +
Math.Cos(origin1.Latitude) * Math.Cos(origin2.Latitude) *
Math.Sin(dLon / 2) * Math.Sin(dLon / 2)));
if (dist12 == 0)
{
return(GeoPoint.Invalid);
}
// initial/final bearings between points
var brngA = Math.Acos((Math.Sin(origin2.Latitude) - Math.Sin(origin1.Latitude) * Math.Cos(dist12)) /
(Math.Sin(dist12) * Math.Cos(origin1.Latitude)));
if (double.IsNaN(brngA))
{
brngA = 0; // protect against rounding
}
var brngB = Math.Acos((Math.Sin(origin1.Latitude) - Math.Sin(origin2.Latitude) * Math.Cos(dist12)) /
(Math.Sin(dist12) * Math.Cos(origin2.Latitude)));
double brng12, brng21;
if (Math.Sin(dLon) > 0)
{
brng12 = brngA;
brng21 = 2 * Math.PI - brngB;
}
else
{
brng12 = 2 * Math.PI - brngA;
brng21 = brngB;
}
var alpha1 = (brng13 - brng12 + Math.PI) % (2 * Math.PI) - Math.PI; // angle 2-1-3
var alpha2 = (brng21 - brng23 + Math.PI) % (2 * Math.PI) - Math.PI; // angle 1-2-3
if (Math.Sin(alpha1) == 0 && Math.Sin(alpha2) == 0)
{
return(GeoPoint.Invalid); // infinite intersections
}
if (Math.Sin(alpha1) * Math.Sin(alpha2) < 0)
{
return(GeoPoint.Invalid); // ambiguous intersection
}
var alpha3 = Math.Acos(-Math.Cos(alpha1) * Math.Cos(alpha2) +
Math.Sin(alpha1) * Math.Sin(alpha2) * Math.Cos(dist12));
var dist13 = Math.Atan2(Math.Sin(dist12) * Math.Sin(alpha1) * Math.Sin(alpha2),
Math.Cos(alpha2) + Math.Cos(alpha1) * Math.Cos(alpha3));
var lat3 = Math.Asin(Math.Sin(origin1.Latitude) * Math.Cos(dist13) +
Math.Cos(origin1.Latitude) * Math.Sin(dist13) * Math.Cos(brng13));
var dLon13 = Math.Atan2(Math.Sin(brng13) * Math.Sin(dist13) * Math.Cos(origin1.Latitude),
Math.Cos(dist13) - Math.Sin(origin1.Latitude) * Math.Sin(lat3));
var lon3 = origin1.Longitude + dLon13;
lon3 = (lon3 + 3 * Math.PI) % (2 * Math.PI) - Math.PI; // normalize to -180..+180º
return(new GeoPoint(lat3.ToDegrees(), lon3.ToDegrees()));
}
public static double Atan2(object self, double y, double x)
{
return(SM.Atan2(y, x));
}
public static double Atan2(object self, [DefaultProtocol] double y, [DefaultProtocol] double x)
{
return(SM.Atan2(y, x));
}
private static int Math_Atan2(ILuaState lua)
{
lua.PushNumber(Math.Atan2(lua.L_CheckNumber(1),
lua.L_CheckNumber(2)));
return(1);
}
public static double TanAngle(Vector vector)
{
return(ReduceAngle(Math.Atan2(vector.Y, vector.X)));
}