[R] x axis

David L Carlson dcarlson at tamu.edu
Thu Oct 13 22:54:44 CEST 2011


There are lots of options since you did not tell us what you want on the
axis (or what you have tried).

For example if you want more than 6 tick marks/labels, replace xlim=c(0,
3000) with xaxp=c(0, 3000, 12) to get labels every 250 meters instead of
500. Depending on the size of the graph window you may need to add
cex.axis=.8 to reduce the text size to fit the labels in the available
space. Likewise xaxp=c(0, 3000, 3) would reduce the number of labels to
every 1000 meters.


-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On
Behalf Of R. Michael Weylandt
Sent: Thursday, October 13, 2011 1:17 PM
To: lauren mcdonagh
Cc: r-help at r-project.org
Subject: Re: [R] x axis

In your plot call, you can use xaxt = "n" to turn off the default x
axis tick marks, then add

axis(1, at  = VARIABLEWHEREYOUWANTTICKMARKS) # If you want ticks at
the x you put in, its just axis(1, at = x)

to get ticks where you want them. There's also a label= argument if
you want them to be labled as something other than the numbers.

Hope this helps,

Michael

On Thu, Oct 13, 2011 at 11:42 AM, lauren mcdonagh
<cleverlollipop at yahoo.ie> wrote:
> Dear R users,
>
> I am quite desperate for help. I haven't used R in a couple of years and
I'm currently finishing a masters project and running out of time to figure
out my problem. I have read and tried the examples on many websites, in your
forums and R Help yet still can't manage to change the x axis. I am using R
2.8.0 on windows.
>
> I'm sure there must be a way to do this as many people's questions seem
more difficult. My problem is that I need to change the numbers on the x
axis from the default.
>
> This is my scatter plot so far:
>
>
>> x <- c(0, 50, 100, 250, 500, 750, 1000, 1500, 2000, 2500, 3000)
>> y <- c(640, 585, 152, 85, 348, 922, 518, 82, 83, 591, 79)
>> plot(y~x, type = "p", xlab = "Distance (m)", ylab = "Concentrations
(mg/kg)", xlim = c(0,3000), ylim = c(0,1000), col ="black", pch = 19, sub =
"Lead", font.sub = 2)
>> text(0,640, "mine average", pos = 4, col = "red", cex= 0.6)
>> abline(h=c(21), lty = 2, col = "green", lwd =1)
>> abline(h=c(36), lty = 3, col = "blue", lwd = 1)
>> abline(h=c(190), lty = 1, col ="red", lwd = 2)
>> legend(1700, 1000, c("Control", "Dutch List - Optimum", "Dutch List -
Action"), col = c(3,4,2), lty = c(2,3,1), cex = 0.8, lwd = c(1,1,2))
>
> R automatically changes the x axis to 0, 500, 100, 1500, 2000, 2500, 3000.
I've tried a few things you've already said to other people with problems
but all I get is error.
>
> I would really appreciate some help as I've no one else to ask (the uni
I've studied my masters in does not use R).
>
> Yours faithfully,
>
> Lauren.
>        [[alternative HTML version deleted]]
>
>
> ______________________________________________
> 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.
>
>

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