[GRASSLIST:1952] Re: topograpic analysis using GRASS and R

[Roger Bivand]

On Wed, 3 Dec 2003, Carlos Henrique Grohmann wrote:

> Hello list, 
> 
> I'm trying to see the realtion beetwen aspect and slope for a given area using
> R. I have in mind a graph with different scales on the axis. For instance, I
> could have the scales for aspect in the bottom (0-360 deg) and left (density)
> axis , and for slope in the top (0-65 deg) and right (density) axis. But I
> don't know how to do this. already searched the web, but without luck. 
> Does anyone already made something like this? 
> 

The usual answer is:

> par(new=TRUE)

then the next plotting command overplots the existing plot. You will need 
to turn off the axes too, and plot them one-by-one separately. There are 
threads on this on the R-help list, but usually then people want to 
overplot on the same bottom x-axis, with varying left and right y-axes for 
two different variables. I'm not sure what you win by overplotting, 
because the densities are not expressing the cell-by-cell relationship, 
which would be shown on a regular plot, if I follow you correctly.

Roger


> thanks for help
> 
> 

-- 
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Breiviksveien 40, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 93 93
e-mail: Roger.Bivand at nhh.no