# eqscplot: Plots with Geometrically Equal Scales

## Description

Version of a scatterplot with scales chosen to be equal on both axes, that
is 1cm represents the same units on each

## Usage

eqscplot(x, y, ratio = 1, tol = 0.04, uin, ...)

## Value

invisibly, the values of `uin`

used for the plot.

## Arguments

- x
vector of x values, or a 2-column matrix, or a list with components
`x`

and `y`

- y
vector of y values

- ratio
desired ratio of units on the axes. Units on the y axis are drawn at
`ratio`

times the size of units on the x axis. Ignored if `uin`

is
specified and of length 2.

- tol
proportion of white space at the margins of plot.

- uin
desired values for the units-per-inch parameter. If of length 1, the
desired units per inch on the x axis.

- ...
further arguments for `plot`

and graphical parameters. Note that
`par(xaxs="i", yaxs="i")`

is enforced, and `xlim`

and
`ylim`

will be adjusted accordingly.

## Side Effects

performs the plot.

## Details

Limits for the x and y axes are chosen so that they include the
data. One of the sets of limits is then stretched from the midpoint to
make the units in the ratio given by `ratio`

. Finally both are
stretched by `1 + tol`

to move points away from the axes, and the
points plotted.

## References

Venables, W. N. and Ripley, B. D. (2002)
*Modern Applied Statistics with S.* Fourth edition. Springer.