R help - Aug 2013 - Kite Diagrams

Dear R help,



I would like to teach my students to do a simple kite diagram with some
simulated data.



I have these columns:

*Forest.Type*

*Altitude.percent*

*Total*

Primary

20

827

Primary

20

917

Primary

10

946

Primary

10

516

Primary

1

775

Primary

1

777

Secondary

20

22

Secondary

20

41

Secondary

10

52

Secondary

10

65

Secondary

1

78

Secondary

1

82



I would like to use Altitude as a proxy for distance and I have 2 readings
for each altitude: one to the supposed right and one to the supposed left
of the transect.



I rather impulsively tried


> kiteChart(t(Total))
Error in varpos[kite] <- varpos[kite - 1] + 1.1 * (kitewidths[kite - 1] +
:

  replacement has length zero



And I’m now at a loss…would anyone be able to help?

Thanks and regards,
Ruth

	[[alternative HTML version deleted]]

On 08/05/2013 04:45 PM, Ruth Chan wrote:
> I would like to teach my students to do a simple kite diagram with some
> simulated data.
>
> ...
> I would like to use Altitude as a proxy for distance and I have 2 readings
> for each altitude: one to the supposed right and one to the supposed left
> of the transect.
>
> ...
> And I?m now at a loss?would anyone be able to help?
>
Hi Ruth,
The kiteChart function displays a series of numeric values as widths of 
a polygon along some numeric dimension. You can get a kite chart of your 
data like this:

forest.data<-read.csv("forest.csv")
forestmat<-matrix(forest.data$Total,nrow=2,byrow=TRUE)
forestmat
      [,1] [,2] [,3] [,4] [,5] [,6]
[1,]  827  917  946  516  775  777
[2,]   22   41   52   65   78   82
kiteChart(forestmat,timelabels=forest.data$Altitude.percent[1:6]))

but I don't think that is what you want. The code below shows my guess 
at what you want, a comparison of "Total" by the altitude variable, 
using the mean of the two observations for each forest type and altitude 
percent.

forestdat<-matrix(forest.data[,2:3],ncol=2)
colnames(forestdat)<-c("Altitude.percent","Total")
forest.total<-matrix(c(by(forestdat[1:6,2],forestdat[1:6,1],mean),
  by(forestdat[7:12,2],forestdat[7:12,1],mean)),nrow=2,byrow=TRUE)
forest.total
      [,1]  [,2]  [,3]
[1,]  776 731.0 872.0
[2,]   80  58.5  31.5
timepos<-c(1,10,20)
kiteChart(forest.total,timelabels=timepos,
  varlabels=c("Primary","Secondary"),xlab="Altitude
percent",
  ylab="Total",main="Forest kite chart")

Jim