[R] Little graph questions!

Paul Johnson
Sun, 17 Feb 2002 16:05:39 -0000

I'm working up a set of small working examples in R to show what various
distributions are and the beauty of the central limit theorem.  Those
example programs are in this directory:

http://lark.cc.ukans.edu/~pauljohn/R/ExampleCode/

You can feel free to use those if you want, or you can send me other
small working example code for R.  The key here is small, self contained
things that show things that R can do and people can run without too
much trouble.

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,")"))


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?


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", 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.

--
Paul E. Johnson                       email: pauljohn at ukans.edu
Dept. of Political Science            http://lark.cc.ku.edu/~pauljohn
University of Kansas                  Office: (785) 864-9086
Lawrence, Kansas 66045                FAX: (785) 864-5700