plot.window               package:base               R Documentation

Set up World Coordinates for Graphics Window

Description:

     This function sets up the world coordinate system for a graphics
     window.  It is called by higher level functions such as
     `plot.default' (after `plot.new').

Usage:

     plot.window(xlim, ylim, log = "", asp = NA, ...)

Arguments:

xlim, ylim: numeric of length 2, giving the x and y coordinates ranges.

     log: character; indicating which axes should be in log scale.

     asp: numeric, giving the aspect ratio y/x.

     ...: further graphical parameters as in `par'.

Details:

     Note that if `asp' is a finite positive value then the window is
     set up so that one data unit in the x direction is equal in length
     to `asp' * one data unit in the y direction.

     The special case `asp == 1' produces plots where distances between
     points are represented accurately on screen.  Values with `asp >
     1' can be used to produce more accurate maps when using latitude
     and longitude.

     Usually, one should rather use the higher level functions such as
     `plot', `hist', `image', ..., instead and refer to their help
     pages for explanation of the arguments.

See Also:

     `xy.coords', `plot.xy', `plot.default'.

Examples:

     ##--- An example for the use of  `asp' :
     library(mva)
     data(eurodist)
     loc <- cmdscale(eurodist)
     rx <- range(x <- loc[,1])
     ry <- range(y <- -loc[,2])
     plot(x, y, type="n", asp=1, xlab="", ylab="")
     abline(h=pretty(rx, 10),
            v=pretty(ry, 10), col= "lightgray")
     text(x, y, names(eurodist), cex=0.5)

