A C# implementation of Geodesic Functions to work with points and paths on the earth's surface using simple spherical trigonometric formulae.

Transcribed from the original JavaScript work by Chris Veness (C) 2005-2016 and published under the same MIT License.

AlongTrackDistance

• Calculate how far the point is along a track from the start-point, heading towards the end-point.
• That is, if a perpendicular is drawn from the point to the (great circle) path, the along-track distance is the distance from the start point to where the perpendicular crosses the path.

AreaOf

• Calculate the area of a spherical polygon where the sides of the polygon are great circle arcs joining the vertices.

Bearing

• Calculate the (initial) bearing from point A to point B.

CrossingParallels

• Calculate the pair of meridians at which a great circle defined by two points crosses the given latitude.

CrossTrackDistance

• Calculate the (signed) distance from point A to great circle defined by start-point and end-point.
• Also known as 'Cross Track Error'

Destination

• Calculate the destination point from point A having travelled the given distance on the given initial bearing.

Distance

• Calculate the distance between 2 points (using haversine formula).

DistanceToLine

• Using the line A->B calculate the shortest distance from point C that line.

DistanceToPlane

• Using a virtual line on the same plane as the line A->B calculate the shortest distance from point C that line.

FinalBearing

• Calculate final bearing arriving at destination point from point A.
• The final bearing will differ from the initial bearing by varying degrees according to distance and latitude.

IntermediatePoint

• Calculate the point at a given fraction along the track between point A and point B.

Intersection

• Calculate the point of intersection of two paths defined by points and bearings.

MaximumLatitude

• Calculate the maximum latitude reached when travelling on a great circle on given bearing from this point ('Clairaut's formula').

Midpoint

• Calculate the midpoint between point A and point B.

PerpendicularPoint

• Calculate the point on the line A->B that is perpendicular from the line to point C.