R: Set up World Coordinates for Graphics Window

plot.window {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)

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