Experience with very-large screen projection of ggplot graphics

[Rob James]

I am producing some graphs that will be part of an upcoming national
conference plenary address (think 7-10K in audience). So, the graphs
will end up on large parallel projection screens at a hotel.conference
site, with I suspect medium resolution displays in a badly lit hall.
The graphicss will likely end up "inside" powerpoint for display purposes

Has anyone done this before, and do you have any reflections on font
size, colour choices, etc. that you could offer? Obviously Tufte's
guidance applies and less is almost always better, and while Hadley has
done a fine job with the defaults, this is a very different graphical
display than paper with high resolution printing. So, experience with
this format of presentation would be most welcome.

Most of the data will be bar charts, box plots, a couple of X/Y graphs,
and some use of geom_crossbar to depict graphically beta estimates and
standard errors from logistic regression models (which, by the way, is a
lovely way to get people to focus on the overall shape of the model
rather than on whether the p value is 0.04 or 0.06).

Suggestions welcome.

Thanks

[hadley wickham]

Hi Rob,

Wow, awesome! I think the main thing is to ensure that your graphics
are high contrast (maybe you'll want theme_bw()), and fill up as much
of the slide as possible - I usually avoid a title, and make the
graphic fill up absolutely every inch of the display. Another thing
to bear in mind is that with a 10k audience, you'll have ~500 colour
blind men in the audience, so make sure to double check your colours.
I particularly recommend color oracle
(http://colororacle.cartography.ch/) for this task.

Hadley

--
http://had.co.nz/

[baptiste auguie]

On Mon, Sep 28, 2009 at 9:11 PM, hadley wickham <h.wi...@gmail.com> wrote:
> Another thing
> to bear in mind is that with a 10k audience, you'll have ~500 colour
> blind men in the audience, so make sure to double check your colours.
> I particularly recommend  color oracle
> (http://colororacle.cartography.ch/) for this task.
>

Good tip, I wish I had known about this website before asking a
related question on r-help this morning!

Coming back to the question, you might want to try,

- define your own custom theme (perhaps: horizontal y-axis labels,
large sans serif font, white background, no box, etc.). It would be
great if you could share such a theme with us afterwards.

- the dichromat colour scales from the dichromat package (an
experimental interface à la scale_colour_brewer() for ggplot2 is in
the package ggextra)

If you were to make the whole presentation by yourself, I'd suggest
you try the tikzDevice package and Sweave + Beamer, but it looks as
though you'll be using powerpoint.

All the best,

baptiste

[dataan...@earthlink.net]

Hi,

If you will be using Powerpoint, I'd like to know how you will get a lot of high quality graphs into Powerpoint. Using S-Plus, it's a snap. I stuggle with R. Anything you can share would be appreciated.

Walt
Sent from my Verizon Wireless BlackBerry

-----Original Message-----
From: baptiste auguie <bapt...@googlemail.com>

Date: Mon, 28 Sep 2009 21:45:41
To: Rob James<r...@aetiologic.ca>
Cc: <ggp...@googlegroups.com>
Subject: Re: Experience with very-large screen projection of ggplot graphics

[James Howison]

FWIW, I've noticed that projectors, especially in a darkened room,
typically err on the warm side, ie they cast everything as though
there was a yellow filter over the top. So while high-contrast will
help there, one additional thing to bare in mind is that yellows will
show even less against the background.

Making the graphics as big as possible is an excellent idea. I've
effectively zoomed in on sections (and then back out again) when I
want more detail. I do that as separate slides, without animation,
since animations cause havoc if you have to move backwards in your
presentation (not so likely for a keynote :) You want to be
particularly careful if you have important parts close to the edge of
your slide, I've found many projectors like to clip small parts of the
edges of slides. If you are going to zoom, you can do that
effectively with a PDF graphic.

Powerpoint has gotten better about handling imported PDFs, in my quick
testing with PP in Mac Office 2008, PDF came through fine. I posted a
while back about handling font sizes, best bet is to generate the
picture at the actual size you want, and do no scaling in Word/
Powerpoint. Use

theme_set(theme_gray(base_size=24)) # or whatever size makes sense for
your slides.
ggsave("test.pdf",width=9,height=7) # 9inx7in is the size that PP
thinks my slides are, according to the rulers.

Note that testing this just now I had some trouble with scales coming
off the edge of the picture at base_size=24. Seems like the Margins
don't get wider along with the base_size?

--J