[R] duplicate data points on a line graph

[Carl Witthoft]

If you want to take the second  approach, it can be relatively easily 
generalized by calculating the cex values based on the count of ordered 
pairs in the original dataset.

Here's a data set:
 > xy
      x y
[1,] 1 4
[2,] 1 5
[3,] 2 3
[4,] 3 3
[5,] 4 5
[6,] 5 2
[7,] 1 4
[8,] 2 3

Here's the same set fully sorted:

xy[order(x,y),]->xyord
      x y
[1,] 1 4
[2,] 1 4
[3,] 1 5
[4,] 2 3
[5,] 2 3
[6,] 3 3
[7,] 4 5
[8,] 5 2

There's gotta be some very simple way to create a series of values for 
cex but I'm missing it, other than a loop like

cexvec<-rep(1,8)
for i in 2:8 {
if (xyord[i,1]==xyord[i-1,1] & xyord[i,2]== xyord[i-1,2] ) {

cexvec[i]<-cexvec[i-1]+1
}
}

You get the idea, sort of  :-)

Carl


On 7/15/2009 2:19 PM, NDC/jshipman wrote:
 > Hi,
 >     I am new to R plot.  I am trying to increase the data point
 > observation when duplicate data points exist
 >
 > x    y
 > 1    10
 > 1    10
 > 2    3
 > 4    5
 > 9     8
 >
 >
 > in the about example  1, 10 would be displayed larger than the other
 > data points.  Could someone give me some assistance with this problem

   A couple of simple approaches:

x <- c(1,1,2,4,9)

y <- c(10,10,3,5,8)

plot(jitter(x), jitter(y))

plot(x, y, cex=c(2,2,1,1,1))

 > 757-864-7114
 > LARC/J.L.Shipman/jshipman
 > Jeffery.L.Shipman at nasa.gov