eqpole: Convert Right Ascension and declination to X,Y using an...

In astrolibR: Astronomy Users Library

Description

Convert Right Ascension and declination to X,Y using an equal-area polar projection

Usage

eqpole(l, b, southpole)

Arguments

l	longitude, in degrees, scalar or vector
b	latitude, in degrees, same number of elements as longitude
southpole	Set to TRUE if plot is centered on the south pole instead of the north pole (optional, default = FALSE)

Details

The output X and Y coordinates are scaled to be between -90 and +90 to go from equator to pole to equator. Output map points can be centered on the north pole or south pole.

Several polar equal-area map projections are provided by the CRAN package mapproj.

Value

X	X coordinate, ranging from -90 to +90, same number of elements as longitude, in degrees
Y	Y coordinate, ranging from -90 to +90, same number of elements as longitude, in degrees

Author(s)

Written by J. Bloch LANL, SST-9 1.1 5/16/91

R adaptation by Arnab Chakraborty (June 2013)

Examples

eqpole(100, -20.)

Example output

$x
[1] 102.6771

$y
[1] -18.10474

astrolibR documentation built on May 2, 2019, 3:26 a.m.