[R] Little graph questions!

Uwe Ligges
Sun, 17 Feb 2002 16:45:18 -0000

Paul Johnson wrote:
>

[...]

> Anyway, I have hit these problems (questions)
>
> 1. When I use paste to edit a title, it inserts spaces where I don't
> want them.
>
> See the picture here:
>
> http://lark.cc.ukans.edu/~pauljohn/R/ExampleCode/gamma4.png
>
> and note that, after the equal signs and the number 1, there is a space
> inserted whenever there is a comma separating text from variable. The
> code in question is:
>
> http://lark.cc.ukans.edu/~pauljohn/R/ExampleCode/template_gamma4.r
>
> the line I use to set the title is:
>
> oneHist <- hist(oneGamma,main=paste("here is one sample from your
> gamma(sh=",sh,",sc=",sc,")"))


See ?paste, what you want is :
 paste(..., sep="")



> 2. Background tint in png output varies in a way I can't understand.
>
> One time I set up a png device and ran the plot and saved it:
>
> http://lark.cc.ukans.edu/~pauljohn/R/ExampleCode/gamma4.png
>
> Another time I forgot to turn on the device, ran the plot, then used
> dev.copy(png, file="poissonCLT",width=500,height=1000) to get:
>
> http://lark.cc.ukans.edu/~pauljohn/R/ExampleCode/poissonCLT.png
>
> in the poissonCLT.png, to my eye the background is light green, while in
> the gamma4.png, it is white. DO you see it too?


Works well for me (R-1.4.1, WinNT4; your version / OS?).
You didn't specify a background color with par(bg=...) before?


> 3. In all of these examples, I have had trouble positioning text in
> figures.  Because I don't know what the plotted values will be until
the
> model is run, it is hard to write coordinates for text(x,y,""). I
> frequently wish there were a way to say "top left part of graph",


You get those coordinates with
 par("usr")


> but the best i can come up with is to find the coordinates of the max or
min
> values of x and y and put the text there.
>
> I have that code in the bottom of this one:
>
> http://lark.cc.ukans.edu/~pauljohn/R/ExampleCode/template_poisson4.r
>
> After using Axum for years, this seems a bit odd to me, but I'm willing
> to do it, if that is what you really intend us to do.


Uwe Ligges