Restrict map to plot domain

This function clips a set of map boundaries exactly to the plot domain.

Usage

map.restrict(bxy,xlim,ylim,xperiod=NA_real_,xfrac=0.5,yperiod=NA_real_,yfrac=NA_real_)
periodicity(domain=.Last.domain())

Arguments

bxy

Number of points to be clicked.

xlim,ylim

Min/max values of the domain.

xperiod, xfrac, yperiod, yfrac

Uually, only the x axis may be periodic for certain projections. xperiod is the numerical value of the total map projection (the domain may be smaller). A jump larger than xfrac * xperiod is assumed to be passing over the boundaries and is thus clipped.

domain

A geodomain.

Details

Usually, a user will never use these functions directly, but they are available just in case. periodicity is a simple function that guesses the periodicity of a map, while map.restrict clips a map to the correct boundaries.

See also

locator

Examples

if (FALSE) {
lalo <- laloclick(2)   # lalo now contains the co-ordinates
points(proj4(lalo),pch='x')   # indicate the points on the present map.
}