Date:         Thu, 7 Dec 2006 22:20:32 -0800
Reply-To:     David L Cassell <davidlcassell@MSN.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         David L Cassell <davidlcassell@MSN.COM>
Subject:      Re: OT: Understand world geography -- in color
In-Reply-To:  <20061207170711.60E4.JWD@uga.edu>
Content-Type: text/plain; format=flowed

jwd@UGA.EDU replied:
>
>toby dunn  wrote:
>
> > As my old prof use to say 'You cant prove squat with a graph, its the
> > numbers, math, and stats that matter'.  When you make a graph the
>graphics
> > should be the bridge between the numbers and something people quickly
> > recognize.  When I look at a graph that has one picture that is big and
> > another small, supposing I recognize the picture, I can make some very
> > limited conclusions,.  But I would also want to know how big are they,
>what
> > is the differents in hard numbers and percentages of teh whole.  Once
>you
> > drop the numbers and distort the thing the person was suppose to
>recognize
> > the graph becomes crap.
>
>If someone wants to distort the facts, it is just as easy to distort a
>numeric based presentation as graphical based one.  If you dislike
>graphics, fine.  That doesn't mean that they are inherently misleading,
>cartograms included.
>
>Jerry
>
>--
>Jerry Davis
>Experimental Statistics
>UGA, CAES, Griffin Campus

Okay Jerry, here I am going to side with you.  I think Toby's
point of view is skewed.  Graphs and plots have a lot of utility.
Would I want to use big stinkin' tables of numbers for regression
diagnostics, instead of using one succinct and clear graph?  No.
The graph is better, because it encapsulates all the relevance of
the (possibly very long) table in one glance.

Do cartograms have utility?  Yes.
Can they be misleading?  Yes.

The human eye tends to equate area with relative value.  So
cartograms based on a world map have to:
[1] start with an equal-area projection of the earth's surface; and
[2] inflate regions based on area measures instead of width or
length measures.

The cartograms we started with do not start from an equal-area
projection.  That was - and is - my primary objection.  Just as I
kvetch about pie charts, because people use non-circular charts,
or circular charts printed in radius-distorting outputs, or charts
which are rotated at an angle, or exploded pie charts which again
distort the *visual detail* and give the user a distorted view.

HTCT,
David
--
David L. Cassell
mathematical statistician
Design Pathways
3115 NW Norwood Pl.
Corvallis OR 97330

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