[R] add reference lines (or grid) in background

[Kenn Konstabel]

There is a "panel.first" argument that can be used with many different
types of plots.

plot(x, panel.first=abline(h=-3:3, lty="dotted", col="gray"), pch=16,
col="red", cex=3)
# red big plotting characters: to show that ablines are drawn before plotting
# the result is different from doing the plot first and abline's after that.

But this doesn't work with boxplot: ablines are drawn (so panel.first
does something) but then overplotted.

boxplot(x, panel.first=abline(h=-3:3,  lwd=100, col="red"))
# lwd=100: this would be absurd if it worked but now I can see only
something red flashing
# on the screen before the boxplot is drawn

Maybe there are some extra parameters to boxplot or bxp (which does
the drawing) that could be used (from what I see on the screen I can
imagine that the ablines are first drawn but deleted by the white
background of boxplot; so it might help to make this background
transparent instead of white; but I haven't examined the code so can't
be sure this is what bxp does). Or it might be easier to do it with
ggplot.

Regards,

Kenn Konstabel


On 9/18/12, John Kane <jrkrideau at inbox.com> wrote:
> Not sure if it is quite the same but ggplot2 does this as its default
> formatting.
>
> library(ggplot2)
> x<-rnorm(100)
> qplot(factor(0),x, geom="boxplot")
>
> John Kane
> Kingston ON Canada
>
>
>> -----Original Message-----
>> From: marongiu.luigi at gmail.com
>> Sent: Tue, 18 Sep 2012 09:35:47 +0100
>> To: r-help at r-project.org
>> Subject: [R] add reference lines (or grid) in background
>>
>> Dear all,
>>
>> Is there a simple way to add reference lines in background? I am trying
>> with
>> abline() or grid() but the lines, since they are executed after the plot
>> function, are draw on top. How can I draw such lines beneath the main
>> plot?
>> Here is an example:
>>
>>
>>
>> x<-rnorm(100)
>>
>> boxplot(x)
>>
>> abline(h=c(-1,0,1))
>>
>> grid(NA, 4, lwd = 2)
>>
>>
>>
>> regards,
>>
>>
>>
>> Luigi Marongiu, MSc
>>
>>
>>
>>
>> 	[[alternative HTML version deleted]]
>>
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>
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