# Calculate the altitude, azimuth and distance of B from A

Source:`R/altitude_azimuth_distance.R`

`altitude_azimuth_distance.Rd`

The altitude (elevation from the horizon), azimuth and distance of a point B from A are the coordinates of the Topocentric Coordinate System as typically used in astronomy to aim your telescope to a heavenly body. It can be also of use to know where an airplane is in the sky with respect to an observer on Earth.

## Arguments

- a
the observer position: a vector of longitude, latitude (in decimal degrees) and altitude (in meters) in WGS84

- b
the observed position: a vector of longitude, latitude (in decimal degrees) and altitude (in meters) in WGS84

## Value

the coordinates in North-East-Up of the observed, B, with respect to the observer A. A vector of altitude

(elevation from the horizon) in decimal degrees,

azimuth) in decimal degrees and distance in meters.

## See also

Other utilities:
`along_track_distance()`

,
`cross_track_distance()`

,
`cross_track_intersection()`