Question

Greetings,

I have three TS variables resembling something like the following:

data <- read.csv(...)
dataA = zoo(data$valueA, data$date)
dataB = zoo(data$valueB, data$date)
dataC = zoo(data$valueC, data$date)

days = seq(start(dataA), end(dataA), "day")

dataAts = na.locf(merge(dataA, zoo(,days)))
dataBts = na.locf(merge(dataB, zoo(,days)))
dataCts = na.locf(merge(dataC, zoo(,days)))

I need to draw dataAts, dataBts and dataCts as a stacked area chart in R. I’ve tried to use plotrix, but I’m not proficient enough to get the matrix in the right form.

Please Note that dataAts, dataBts and dataCts are not already accumulated, so it is not just a matter of drawing the three of them in the correct order (unless you can come up with a way of summing them up on-the-fly).

Can anyone PLEASE help me?

Thanks in advance…

Answer 1

How about something like this?

library(zoo)
library(ggplot2)

data <- data.frame(date=Sys.Date()+1:30,
  valueA=runif(30), valueB=runif(30), valueC=runif(30))

dataA = zoo(data$valueA, data$date)
dataB = zoo(data$valueB, data$date)
dataC = zoo(data$valueC, data$date)

days = seq(start(dataA), end(dataA), "day")

dataAts = na.locf(merge(dataA, zoo(,days)))
dataBts = na.locf(merge(dataB, zoo(,days)))
dataCts = na.locf(merge(dataC, zoo(,days)))

dataABCts <- merge(dataAts,dataBts,dataCts)

# EDIT: Change labels here
colnames(dataABCts) <- c("stock1","stock2","stock3")

stacked <- lapply(colnames(dataABCts),function(i) {
  data.frame(date=index(dataABCts),values=dataABCts[,i],ind=i)
})
stacked <- do.call(rbind,stacked)

ggplot(stacked, aes(x=date, y=values)) + geom_area(aes(fill=ind))