[R] plot scale

[Ryan]

> 
> Hi,
> 
> Is there a way to set the scale of a plot (i.e. number of axis units
> per centimeter) when you output it to postscript? If not, how am I
> supposed to plot graphs with different axis limits to the same scale?
> They just get resized to fit the paper so that graphs which show a
> smaller number of axis units end up with a larger scale.
> 
> Cheers,
> 
> Ben
> 

If I understand you correctly, you want the units on each axis to 
be physically represented equally on the same scale.  If this is right, 
try using the lattice package (xyplot, etc.) with aspect="iso".

Lattice lets you adjust the aspect ratio of the plot to whatever you 
like and constrains the dimensions of the plot accordingly.  Base 
graphics also allow for control of the aspect ratio using "asp=", but 
extend the limits of the plot to fill whatever region you are plotting 
in.