mark sections on a time chart

Hello,

The function below requires package plotrix and is far from fully 
tested, but it might do what you want.


library(zoo)


arrowsRange <- function(from, to, at = 1, labels = NULL,
    length = 1/8, horizontal = TRUE, border = FALSE, ...){
    require(plotrix)
    f1 <- function(){
        if(horizontal)
            arrows(from, at, to, at, length = length, code = 3, ...)
        else
            arrows(at, from, at, to, length = length, code = 3, ...)
    }
    f2 <- function(){
        f1()
        if(horizontal){
            x <- rowMeans(cbind(from, to))
            y <- at
        }else{
            x <- at
            y <- rowMeans(cbind(from, to))
        }
        boxed.labels(x, y, labels = labels, border = border)
    }
    if(is.null(text)) f1() else f2()
}


# Make up some test data
set.seed(9365)
z <- zoo(cumsum(rnorm(365)))
index(z) <- Sys.Date() + 1:365
start <- as.Date(c("2012-12-21", "2013-03-21", "2013-06-22"))
end <- as.Date(c("2013-03-20", "2013-06-21", "2013-09-21"))
seasons <- c("Winter", "Spring", "Summer")

plot(z)
abline(v = c(start[1], end))


Hope this helps,

Rui Barradas

Em 20-10-2012 07:33, Christof Klu? escreveu:

Hi

is there a comfortable way to mark periods on time chart (axis.Date)?

To do it with arrows(...), seems to be irritating.

I want to have something like

<---winter--><--spring--><--summer-->

thx
Christof