[R] specify axis range

[Gavin Simpson]

On Tue, 2010-08-31 at 17:18 +0100, Lathouri, Maria wrote:
> Dear all,
> 
> I want to make a plot where I can specify the range of y axis. I am using the interaction.plot command and because the values of y axis are from 2 to 500, I am using a logarithmic scale.
> 
> >interaction.plot(speclong$Date,speclong$time2,speclong$outcome,xaxt="n",type="l",pch=20,xlab="", log="y", ylab="Concentration (ug/L)",trace.label="",col=rainbow(7))
> 
> 
> 
> The plot itself gives me a y scale displaying ticks at 2, 5, 10, 20, 100, 200, 500. I would like to get a y scale where it would display ticks at every 4 marks, at 2, 20, 100 and 500.
> 
> 
> 
> I tried ylim=c(2,20,100,500) but nothing happened. Actually I got an error.

ylim needs to be the extreme limits of the axis, i.e. a vector of length
2.

Suppress axis plotting and then draw your own:

interaction.plot(...., axes = FALSE)
axis(2, at = c(2,20,100,500))

E.g., using the example in ?interaction.plot

> with(ToothGrowth, interaction.plot(dose, supp, len, fixed=TRUE, axes = FALSE))
> axis(2, at = c(10, 20))
> axis(1)
> box()

Does that help?

G

> 
> 
> 
> Could you help me?
> 
> 
> 
> Thank you.
> 
> 
> 
> Maria
> 
> 
> 	[[alternative HTML version deleted]]
> 
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