[R] Point size problem

[Prof Brian Ripley]

On Thu, 26 Jun 2008, Marcin Kozak wrote:

> Sorry. I'm using Windows XP and R 2.7.0, and the same problem occurred
> for various graphics devices (windows, pdf, jpeg).

I don't see it for pdf -- that's probably a viewer artefact and you need 
to look at higher resolution.

For windows() and jpeg() it is rasterization.

>
> Marcin
>
> On Thu, Jun 26, 2008 at 11:54 AM, Prof Brian Ripley
> <ripley at stats.ox.ac.uk> wrote:
>> On Thu, 26 Jun 2008, Marcin Kozak wrote:
>>
>>> Hi all,
>>>
>>> I have a simple question and couldn't find any post on this. When
>>> plotting simple scatterplots (other plots as well), e.g.,
>>>
>>> x<-rnorm(30, 10, 1)
>>> y<-rnorm(30, 10, 1)
>>> plot(x, y, pch = 15, cex = 1),
>>>
>>> the points, even those close to each other, may have visibly different
>>> sizes. Do you know what's going on with that?
>>
>> No, because you haven't followed the posting guide and told us your OS, R
>> version and what graphics device this is.
>>
>> This may be an artefact of rasterization in the device, since you are
>> plotting squares with numeric (not integer) coordinates, and these need to
>> be mapped to pixels on a screen device.  So for example the interval (3.7,
>> 6.0) might light up 3 pixels, and (3.4, 5.7) might light up 4.
>>
>>>
>>> Thanks in advance,
>>> Marcin
>>>
>>> ______________________________________________
>>> R-help at r-project.org mailing list
>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>> PLEASE do read the posting guide
>>> http://www.R-project.org/posting-guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>>>
>>
>> --
>> Brian D. Ripley,                  ripley at stats.ox.ac.uk
>> Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
>> University of Oxford,             Tel:  +44 1865 272861 (self)
>> 1 South Parks Road,                     +44 1865 272866 (PA)
>> Oxford OX1 3TG, UK                Fax:  +44 1865 272595
>>
>
>
>
> -- 
> "Build up your weaknesses until they become your strong points" -- Knute Rockne
>

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595