R help - Sep 2014 - Depth vs Temp graph for different transects

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


TAll <- read.csv("TAll Data.csv")


# 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)

# add lines
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])
}

# add a legend
legend(xrange[-2], yrange[-2], 1:nTrans, cex=0.8, col=colors,
  pch=plotchar, lty=linetype, title="Transect")



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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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
>
>
> TAll <- read.csv("TAll Data.csv")
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$Depth)
>
> # set up the plot
> plot(xrange, yrange, ylim = rev(yrange), type="n",
xlab="Temp (deg
> C)",
>  ylab="Depth (m)" )
> colors <- rainbow(nTrans)
> linetype <- c(1:nTrans)
> plotchar <- seq(1,1+nTrans,1)
>
> # add lines
> for (i in 1:nTrans) {
>  tree <- subset(TAll, Trans==i)
>  lines(tree$Temp, tree$Depth, type="b", lwd=1.5,
>    lty=linetype[i], col=colors[i], pch=plotchar[i])
> }
>
> # add a legend
> legend(xrange[-2], yrange[-2], 1:nTrans, cex=0.8, col=colors,
>  pch=plotchar, lty=linetype, title="Transect")
>
If nTrans is 22 then you are getting what you ask for. If you  
subsetted a dataset where TAll$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
>
> 	[[alternative HTML version deleted]]
>
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