[R] quick square root axes

[baptiste auguie]

On 5 May 2009, at 19:28, Duncan Murdoch wrote:

> On 5/5/2009 1:05 PM, Markus Loecher wrote:
>> Dear R users,
>> while I enjoy the built-in log argument to the plot() function, I  
>> wished it
>> would be as easy to create more general custom transformed axes  
>> such as
>> sqrt(), logit, etc...
>>
>> for example, instead of
>> plot(x=exp(rnorm(10)), y=(1:10)^4, log = "xy"), sth. along the  
>> lines of
>> plot(x=exp(rnorm(10)), y=(1:10)^4, trans = list(x = log, y = sqrt))
>> to encode the desired transfomation.
>>
>> This involves just transforming the xy values and creating nice  
>> tick marks
>> at the appropriate positions.
>> Before trying to write my own function, I wanted to see if that
>> functionality already exists in another package ?
>


Have you tried ggplot2? I think Hadley has given a lot of thinking on  
this sort of issues.

http://had.co.nz/ggplot2/
http://had.co.nz/ggplot2/coord_trans.html

baptiste



> I don't know of such a thing, but it may well exist.
>
> If you do write your own, the hardest part will be picking the nice  
> tick
> marks.  They should be approximately evenly spaced, but at nice round
> values of the original variable:  that's hard to do in general.  R has
> the pretty() function for the linear scale, and doesn't do too badly  
> on
> log axes, but you'll need to work out your own rules for the sqrt or
> other scales.
>
> Duncan Murdoch
>
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_____________________________

Baptiste Auguié

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