[R] additional axis, different scale

[David Winsemius]

On May 10, 2012, at 8:07 AM, John Kane wrote:

> I don't think there is any other way.

There is:

a  <- c(10, 20, 30, 40)
b  <- c(50, 250, 500, 600)
ba <- b/a

par(las=1, mar=c(5,5,.5,5))
plot(a,b,     type="b", pch=22, cex=2, col=4, lwd=2, ylim=c(0,650),
xlim=c(0,45))
par(new=TRUE)
plot(a,ba,type="b", pch=21, cex=2, col=2, lwd=2, lty=1, xlim=c(0,45),  
yaxt="n")
  axis(4, at=c(seq(0,25,length=6)), lab=c(seq(0,25,length=6)),  
col.axis=2 )

# could also specify ylim of c(0,25) to the second plot call.

# probably want to have ylab="" in one or both of those plot calls, too.

But I do agree this can be considered deceptive plotting practice.

-- 
David.

> On the other hand, most gurus suggest that a dual scales on a graph  
> are not a good thing.
>
> What about using a two panel graph?
>
> Quick rejigging of your code :
> =================================================================
> a  <- c(10, 20, 30, 40)
> b  <- c(50, 250, 500, 600)
> ba <- b/a
>
> op  <-  par(las=1, mar=c(5,5,.5,5), mfrow=c(2, 1))
> plot(a,b,     type="b", pch=22, cex=2, col=4, lwd=2, ylim=c(0,650),
> xlim=c(0,45))
> plot (a,ba, type="b", pch=21, cex=2, col=2, lwd=2, lty=1)
> par(op)
> ==================================================================
>
>
>
> John Kane
> Kingston ON Canada
>
>
>> -----Original Message-----
>> From: pannigh at gwdg.de
>> Sent: Thu, 10 May 2012 04:37:37 -0700 (PDT)
>> To: r-help at r-project.org
>> Subject: [R] additional axis, different scale
>>
>> Dear list,
>> I am looking for a possibility to present results in a more  
>> graphical way
>> by
>> adding an axis. But I have trouble relating my data to the added  
>> axis.
>> Imagine the following example:
>>
>> a  <- c(10, 20, 30, 40)
>> b  <- c(50, 250, 500, 600)
>> ba <- b/a
>>
>> par(las=1, mar=c(5,5,.5,5))
>> plot(a,b,     type="b", pch=22, cex=2, col=4, lwd=2, ylim=c(0,650),
>> xlim=c(0,45))
>>  axis(4, at=c(seq(0,600,length=6)), lab=c(seq(0,25,length=6)),
>> col.axis=2 )
>>  lines(a,ba, type="b", pch=21, cex=2, col=2, lwd=2, lty=1)
>>
>> I want the red line to relate its values to the x-axis (a) and axis  
>> 4 (on
>> the right) and not as usual to the x-axis (a) and the y-axis (b).
>> This would show the tendency of the red line much clearer which now  
>> can't
>> be
>> seen because of the very different scaling.
>> E.g. I want R to know that I am trying to plot the first point of  
>> the red
>> line P1(50/5) using the x-axis and the right axis, not the y-axis  
>> on the
>> left ect.
>>
>> I would like to solve this without using a factor solution like:
>>  bb <-600/25 * ba
>>  lines(a,bb, type="b", pch=21, cex=2, col=3, lwd=2, lty=1)
>>
>>
>> For any kind of help I would be grateful !
>>
>> --
>> View this message in context:
>> http://r.789695.n4.nabble.com/additional-axis-different-scale-tp4623210.html
>> Sent from the R help mailing list archive at Nabble.com.
>>
>> ______________________________________________
>> 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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David Winsemius, MD
West Hartford, CT