# Compute the along-track distance from a great circle arc

Source:`R/along_track_distance.R`

`along_track_distance.Rd`

Compute the along-track distances of a body, `b` (for example a ground level projection position of an aircraft), from two geographical coordinates, `a1` and `a2` (for example an airport's runway thresholds), of a great circle arc.

## Arguments

- b
the geographical coordinates (WGS84) of a body: a vector of longitude, latitude (in decimal degrees) and eventually altitude (in meters)

- a1
the geographical coordinates (WGS84) of one end of a great circle arc: a vector of longitude, latitude (in decimal degrees) and eventually altitude (in meters)

- a2
the geographical coordinates (WGS84) of the other end of a great circle arc: a vector of longitude, latitude (in decimal degrees) and eventually altitude (in meters)

## See also

Other utilities:
`altitude_azimuth_distance()`

,
`cross_track_distance()`

,
`cross_track_intersection()`