
Well,
 
I agree that plots with multiple y-axes can be very confusing but .... i am not sure that always they are also misleading .... One time i was asked to make a 2 y-axes plot, one y axes was for elevation (heights in meters) and one for rugosity (values between 1 and 2 - unitless). The idea was to visualize that for a more complex profile the rugosity is higher than for a flatter terrain. A correlation coefficient between elevation and rugosity does not show anything, although depending which formula you use for calculating rugosity, it can nicely correlate with slope. Rugosity is a measure of the complexity of the terrain but is quite independent of elevation.
 
I am not sure if this example meets your approval, but i don't think it is misleading ;-)
 
Monica
_______________________________________________________________

Message: 49Date: Fri, 28 Sep 2007 12:13:46 -0500From: "hadley wickham" <h.wickham@gmail.com>Subject: Re: [R] Graphics and LaTeX documents with the same fontTo: "Frank E Harrell Jr" <f.harrell@vanderbilt.edu>Cc: R-help <r-help@stat.math.ethz.ch>Message-ID:<f8e6ff050709281013i7209b684r63aa0d8fcd69d4ef@mail.gmail.com>Content-Type: text/plain; charset=ISO-8859-1 > Yes there is harm. But to make bold lines, easy to read titles is fine.> See the spar function in> http://biostat.mc.vanderbilt.edu/SgraphicsHints for a starter. Also see> the setps, ps.slide, and setpdf functions in the Hmisc package. I was interested to see that you have code for drawing scatterplotswith multiple y-axes. As far as I know the only legitimate use for adouble-axis plot is to confuse or mislead the reader (and this is nota very ethical use case). Perhaps you have a counter-example? Hadley 
_________________________________________________________________


	[[alternative HTML version deleted]]

