You're right - easily tested by just re-sizing the graphics box - sort of counter-intuitive until I remember the clue is in the name - this generates a CIRCLE, come what may...

Stuart

From: Sarah Goslee [mailto:sarah.goslee@gmail.com]
Sent: 19 July 2012 11:18
To: Stuart Leask
Cc: r-help@r-project.org
Subject: Re: [R] 'symbols' not plotting correct circle radii



On Thursday, July 19, 2012, Stuart Leask wrote:
(Oh, and yes I've tried setting 'inches=F', but I then get a circle correct on X axis,  but too large on the Y axis.)

We're back to "read the help." ?symbols explictly states that if inches=FALSE and the axis scales are different, then the x axis coordinates will be used.

And if your axes are different, why would you expect a *circle* to fit both simultaneously?

Perhaps instead you need plot.ellipse from the plotrix package.


Sarah



-----Original Message-----
From: r-help-bounces@r-project.org<javascript:;> [mailto:r-help-bounces@r-project.org<javascript:;>] On Behalf Of Stuart Leask
Sent: 18 July 2012 11:03
To: r-help@r-project.org<javascript:;>
Subject: [R] 'symbols' not plotting correct circle radii

Hi there.

I have been plotting some circles using 'symbols', with radii representing my data, but the radii looked incorrect.

It seems to happen with a single circle too:

Symbols ( 0, 0, circles = 40, xlim = c(-40, 40), ylim= c(-40, 40))

If I put a ruler up to my monitor (technology!)  to compare the radius with the axes, the circle isn't radius 40; it is closer to 15...

I suspect there is a simple answer.


--
Sarah Goslee
http://www.stringpage.com
http://www.sarahgoslee.com
http://www.functionaldiversity.org
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