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 ?
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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