gcp {Rsac} | R Documentation

## GREAT-CIRCLE-PATH PARAMETERS

### Description

Calculates the azimuth and back azimuth of the great-circle-path between two points (source and receiver) on a sphere.

### Usage

    gcp(s, e)

### Arguments

`s` | receiver, or station. This is a list with elements `lat` and `lon` given in degrees.
`e` | epicenter, or source. This is a list with elements `lat` and `lon` given in degrees.

### Value

a list containing the following elements:

`C` | azimuth, in degrees.
`B` | back azimuth, in degrees.
`a` | arc distance, in degrees.
`lat` | latitude defining the path.
`lon` | longitude defining the path.

### Author(s)

Eric M. Thompson <eric.thompson@tufts.edu>

### References

Lay, T. and T. C. Wallace, (1995) Modern Global Seismology, International geophysics series; v. 58, San Diego: Academic Press.

[Package Rsac version 0.1-8 Index]