[R] Multiple series plot with different 'type' argument

[Dirk Eddelbuettel]

On 24 July 2005 at 12:27, Ruben Roa wrote:
| Hi:
| I need to plot two time series in the same plot and
| they cover the same time range and have the same 
| frequency. With 
| RSiteSearch("multiple series plot") 
| i found this post by Gabor Grothendieck:
| http://finzi.psych.upenn.edu/R/Rhelp02a/archive/42281.html
| Exactly what i need except for one detail. I want one series
| to be made of points and the other by a line. When I simply
| try:
| xts <- ts(x$b,start=x$a[1]) 
| yts <- ts(y$b,start=y$a[1]) 
| ts.plot(xts,yts,type=c("p","l"))
| or if i use the 'type' argument inside gpars=list()
| i get an error of "invalid plot type".
| Then if i try
| ts.plot(xts,yts,type1="p",type2="l")
| i get warnings about NAs introduced by coercion and the
| plot still shows two lines.
| Is there any other way i can get these two time series
| in the same plot one with points and the other with lines?
| Any help much appreciated.

Yes, you can, but it requires a little bit of tinkering. Here is a complete
example with two random series. I prefer zoo as a container over ts(). You
can easily change the plotting styles to get points instead of lines etc pp.


library(zoo)

## make up an date index
index <- Sys.Date() + seq(-99,0,by=1)

## init random number generato
set.seed(42)
## and create two random series, with the date index
X1 <- zoo(cumsum(rnorm(100)), index)
X2 <- zoo(cumsum(rnorm(100)), index)

## plot series, suppress axes, set limit to range of both series
oldpar <- par(mar=c(4,4,2,4))           # extra space on the right
plot(X1, col='blue', ylab="X1", type='l', xaxs="i", ylim=range(X, Y))
axis(2, col.axis='blue')                # y-axis for X1, overplotting
grid()                                  # prettier 

par(new=TRUE)                           # add to the plot
plot(X2, col='green', type='l', ylab="", axes=FALSE, xaxs="i", ylim=range(X, Y))
axis(4, col.axis='green')
## need mtext() to annotate 2nd y-axis as title() doesn't do it
mtext("X2", side=4, line=2) 


Hope this helps, Dirk

-- 
Statistics: The (futile) attempt to offer certainty about uncertainty.
         -- Roger Koenker, 'Dictionary of Received Ideas of Statistics'