R help - Jun 2008 - Layout() coordinates and drawing lines / segments

Hello,

I am trying to wrap my head around the coordinates systems associated with
the layout() function ...with the end goal of simply drawing a decorative
line in the upper margin of my figure, which is composed of three plots.

My output is defined as this:

----------------------------------------------------------------------------
     postscript("out.ps", horizontal=FALSE,
     +width=7.5,height=11.5,pointsize=10, paper = "special" )

     opar <- par(omi=c(0.1,0.1,0.1,0.1))

     layout_mat = matrix(c(1,2,3),nrow=3,ncol=1,byrow=TRUE)
     my_layout <-
layout(layout_mat,widths=c(1,1,1),heights=c(1,1.5,1.5),respect=FALSE)

-----------------------------------------------------------------------------

2 Questions:
How do i find what are the x,y's of the upper margin ?
(I've heard of locator() but i don't think i can use it here as i have
an
output file)

And, also, am i allowed to draw lines using segments() or lines() in the
margin regions -- defined by omi, oma -- of my figure, or are those
functions confined to plot regions ?


Thank You a lot,
maria

Hi

Take a look at ...

http://www.stat.auckland.ac.nz/~paul/R/basegraphics.pdf

... it's getting old, but a lot of what it says should still hold,
especially the stuff about coordinate systems and what you can draw where.

Paul


maria at meteo.mcgill.ca wrote:
> Hello,
> 
> I am trying to wrap my head around the coordinates systems associated with
> the layout() function ...with the end goal of simply drawing a decorative
> line in the upper margin of my figure, which is composed of three plots.
> 
> My output is defined as this:
> 
>
----------------------------------------------------------------------------
>      postscript("out.ps", horizontal=FALSE,
>      +width=7.5,height=11.5,pointsize=10, paper = "special" )
> 
>      opar <- par(omi=c(0.1,0.1,0.1,0.1))
> 
>      layout_mat = matrix(c(1,2,3),nrow=3,ncol=1,byrow=TRUE)
>      my_layout <-
> layout(layout_mat,widths=c(1,1,1),heights=c(1,1.5,1.5),respect=FALSE)
> 
>
-----------------------------------------------------------------------------
> 
> 2 Questions:
> How do i find what are the x,y's of the upper margin ?
> (I've heard of locator() but i don't think i can use it here as i
have an
> output file)
> 
> And, also, am i allowed to draw lines using segments() or lines() in the
> margin regions -- defined by omi, oma -- of my figure, or are those
> functions confined to plot regions ?
> 
> 
> Thank You a lot,
> maria
> 
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-- 
Dr Paul Murrell
Department of Statistics
The University of Auckland
Private Bag 92019
Auckland
New Zealand
64 9 3737599 x85392
paul at stat.auckland.ac.nz
http://www.stat.auckland.ac.nz/~paul/