# [R] Depth vs Temp graph for different transects

David Winsemius dwinsemius at comcast.net
Mon Sep 1 18:32:29 CEST 2014

```On Sep 1, 2014, at 3:52 AM, Tinus Sonnekus wrote:

> Hi All,
>
> Have the following code. The graph works well plotting the 15
> transect for
> me however the legend shows a total of 22 transects. The original
> data has
> 22 transects numbered from 1 to 22. New data set got only 15. How
> can I get
> the legend to show only the transects plotted.
>
>
> # Create Line Chart
>
>

You have set up a situation where we can only guess.

>
>
> # convert factor to numeric for convenience
> TAll\$Tran <- as.numeric(TAll\$Trans)
> nTrans <- max(TAll\$Trans)
>
> # get the range for the x and y axis
> xrange <- range(TAll\$Temp)
> yrange <- range(TAll\$Depth)
>
> # set up the plot
> plot(xrange, yrange, ylim = rev(yrange), type="n", xlab="Temp (deg
> C)",
>  ylab="Depth (m)" )
> colors <- rainbow(nTrans)
> linetype <- c(1:nTrans)
> plotchar <- seq(1,1+nTrans,1)
>
> for (i in 1:nTrans) {
>  tree <- subset(TAll, Trans==i)
>  lines(tree\$Temp, tree\$Depth, type="b", lwd=1.5,
>    lty=linetype[i], col=colors[i], pch=plotchar[i])
> }
>
> legend(xrange[-2], yrange[-2], 1:nTrans, cex=0.8, col=colors,
>  pch=plotchar, lty=linetype, title="Transect")
>
If nTrans is 22 then you are getting what you ask for. If you
subsetted a dataset where TAll\$Trans was a factor then it's perfecty
possible that the legend would have more items than the subset.
Perhaps you should use `length` or length(unique(.))` rather than `max`.

--
David.

>
>
> Thanks for the help,
> Tinus
>
> --
> M.J. Sonnekus
> PhD Candidate (The Phytoplankton of the southern Agulhas Current Large
> Marine Ecosystem (ACLME))
> Department of Botany
> South Campus
> Nelson Mandela Metropolitan University
> PO Box 77000
> Port Elizabeth
> South Africa
> 6031
>
> Cell: 082 080 9638
> E-mail: tsonnekus at gmail.com
>
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