Katrina,
What I have done, if I understand what you are after, was to create a list for
each month of data - in order. Then, create a boxplot - in order - by
month/year. I do this for our ensemble streamflow forecasts. The key us to
create the list of values by month.
Regards,
Tom
Sent from my iPhone
On Feb 16, 2011, at 3:31 PM, Katrina Bennett <kebenn...@alaska.edu> wrote:
> Hello, I'm trying to develop a box plot of time series data to look at the
> range in the data values over the entire period of record.
>
> My data initially starts out as a list of hourly data, and then I've been
> using this code to make this data into the final ts array.
>
> # Read in the station list
> stn.list <- read.csv("/home/kbennett/fews/stnlist3", as.is=T, header=F)
>
> # Read in all three variables.
> vars <- c("MAT", "MAP", "MAP06")
>
> for (stn in stn.list) {
> for (v in 1:length(vars) {
> # Read in year month start and end dates table & name it
> ym.table <- read.csv("/home/kbennett/fews/", stn, var, ".ym.txt", as.is=T,
> header=F)
> names(ym.table) <- c("yearstart", "monthstart", "yearend", "monthend")
>
> fn <- paste(stn, ".", vars[v], ".FIN", sep="")
> if(file.exists(fn)) {
> clim.dat <- read.csv(fn, header=F)
> names(clim.dat) <- c("cdata")
> year.start <- ym.table$yearstart
> year.end <- ym.table$yearend
>
> mo.start <- ym.table$monthstart
> mo.end <- ym.table$monthend
>
> regts.start = ISOdatetime(year.start, mo.start, 1, hour=0, min=0,
> sec=0, tz="GMT")
> regts.end = ISOdatetime(year.end, mo.end, 1, hour=18, min=0, sec=0,
> tz="GMT")
>
> zts <- zooreg(clim.dat$cdata, start = regts.start, end = regts.end,
> frequency = 4, deltat = 21600)
>
> #Create a daily average from the timeseries
> zta <- aggregate(zts, as.POSIXct(cut(time(zts), "24 hours",
> include=T)), mean)
>
> #Select hourly data from the timeseries based on a specific time
> zt.hr <- aggregate(zts, as.Date, head, 4)
> zt.hr.ym <- aggregate(zt.hr, as.yearmon, head, 4)
> zt.hr.1 <- zt.hr.ym[,1]
> zt.hr.2 <- zt.hr.ym[,2]
> zt.hr.3 <- zt.hr.ym[,3]
> zt.hr.4 <- zt.hr.ym[,4]
>
> zt.hr.1a <- aggregate(zt.hr.1, as.yearmon)
> min.y <- min(zt.hr)
> max.y <- max(zt.hr)
>
> frequency(zt.hr.1) <- 12
> zt.1.mo <- as.ts(zt.hr.1)
>
> #Monthly boxplots of daily averages, for the months
> boxplot(zt.1.mo ~ month, ##THIS IS WHAT DOESN'T
> WORK HERE
> boxwex=0.25, at=(1:12)-0.2,
> outline = F,
> col = "gray",
> xlab = "Month",
> ylab = expression(paste("( ",T^o,"C )") ),
> ylim = c(min.y-5,max.y+5),
> yaxs = "i",
> xaxt = "n",
> main = vars)
> axis(1, at=c(1:12), labels=month.abb, cex.axis = 0.65)
> legend("topright", c("Hour 00"), fill = c("gray"))
> }
>
>
>
> #write the results to a csv file
> write.csv(cdat, paste(stn, "_", vars[v], ".csv", sep=""),
> row.names=T, col.names=T)
>
> }
> }
>
>
> The final array looks like this:
>
> Jan Feb Mar Apr May Jun Jul Aug Sep
> Oct Nov Dec
> 1948 28.719 4.977 39.037 9.746 8.348 36.672 47.660 54.076 38.062 34.486
> 11.938 39.666
> 1949 11.698 -6.675 16.844 0.950 10.349 38.752 39.785 40.544 57.603 35.476
> 2.308 -7.960
> 1950 0.340 45.206 6.385 17.132 19.074 38.465 48.711 54.686 48.743 33.978
> 23.090 10.007
> 1951 12.398 31.304 47.182 4.539 23.223 45.668 50.516 53.239 59.402 28.081
> 16.427 14.839
> 1952 -7.693 30.561 33.478 14.799 12.750 35.359 43.180 57.840 44.593 43.768
> 8.574 14.587
> 1953 -9.875 38.726 26.393 12.881 19.228 48.833 49.903 56.224 48.829 23.783
> 19.308 14.292
> 1954 35.943 16.706 16.021 7.806 23.593 40.418 45.310 53.113 49.203 29.480
> 17.228 33.068
> 1955 23.363 15.706 14.100 17.271 19.258 36.969 47.301 51.826 40.446 35.201
> 16.463 11.132
> 1956 45.868 -8.504 48.167 10.746 25.024 36.247 47.741 52.160 41.781 29.115
> 25.414 21.954
>
>
>
> My main problem is that I can't access the rows (i.e. months) to subset the
> data by.
>
> Could someone point out how I am able to get at the months in this array and
> subset them for plotting using the boxplot function?
>
>
> Thank you,
>
> Katrina
>
> --
> Katrina E. Bennett
> PhD Student
> University of Alaska Fairbanks
> International Arctic Research Center
> 930 Koyukuk Drive, PO Box 757340
> Fairbanks, Alaska 99775-7340
> 907-474-1939 office
> 907-385-7657 cell
> kebenn...@alaska.edu
>
>
> Personal Address:
> UAF, PO Box 752525
> Fairbanks, Alaska 99775-2525
> bennett.katr...@gmail.com
>
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>
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