CircleCoordinates: Circle coordinates on a sphere

In EarthSystemDiagnostics/ecustools: A miscellaneous collection of R functions for working with time-series and paleo data.

Description

Get the latitude and longitude coordinates of a circle with a given radius drawn onto the surface of a sphere.

Usage

CircleCoordinates(
  lat0,
  lon0,
  radius.circle,
  radius.sphere = 6357,
  n = 100,
  return.pi.interval = FALSE
)

Arguments

lat0	geographical latitude [degree] of circle centre.
lon0	geographical longitude [degree] of circle centre.
radius.circle	radius of the circle; in the same units as radius.sphere.
radius.sphere	radius of the sphere on whose surface the circle is drawn; i.e. typically Earth's radius. Default value is Earth's polar radius which gives slightly more accurate results for drawing circles close to either one of the poles. Adjust to equatorial radius for drawing circles in the mid-latitudes.
n	number of polar angle increments to draw the circle.
return.pi.interval	if TRUE, return the circle's longitudes in the interval [-pi, pi]; else in [0, 2*pi].

Value

data frame of circle latitude (lat) and longitudes (lon) in geographical coordinates in degree for the number of incremental steps specified by n (given as the polar coordinate phi).

Author(s)

Thomas Münch

EarthSystemDiagnostics/ecustools documentation built on Jan. 15, 2022, 5:22 p.m.