berryFunctions (version 1.12.3)

seasonality: Seasonality analysis

Description

Plot time series to examine it for seasonality

Usage

seasonality(dates, values, data, drange = NULL, vrange = NULL, shift = 0, janline = TRUE, nmax = 0, maxargs = NULL, plot = 1, months = substr(month.abb, 1, 1), xlab = "Year", ylab = "Month", zlab = substitute(values), ylim = NA, xaxs = "r", yaxs = "i", main = "Seasonality", adj = 0.2, mar = c(3, 3, 4, 1), mgp = c(1.7, 0.7, 0), keeppar = TRUE, legargs = NULL, ...)

Arguments

dates

Dates in ascending order. Can be charater strings or strptime results, as accepted (and coerced) by as.Date

values

Values to be mapped in color with colPoints

data

Optional: data.frame with the column names as given by dates and values

drange

Optional date range (analogous to xlim), can be a vector like dates. DEFAULT: NULL

vrange

Optional value range (analogous to ylim), can be a vector like values. DEFAULT: NULL

shift

Number of days to move the year-break to. E.g. shift=61 for German hydrological year (Nov to Oct). DEFAULT: 0

janline

Logical: Should horizontal line be plotted at January 1st if shift!=0? DEFAULT: TRUE

nmax

Number of annual maxima to be marked, plotted and returned. Currently, only 0 and 1 are implemented. DEFAULT: 0

maxargs

List of arguments passed to lines for annual maxima, e.g. maxargs=list(type="l", col="red", lty=3). DEFAULT: NULL

plot

Integer specifying the type of plot. Can be a vector to produce several plots. 0: none, only data.frame with annual maxima. 1: color coded doy (day of the year) over year (the default). 2: Color coded spiral graph with spiralDate. 3: Spaghetti line plot with discharge over doy, one line per year. 4: plot of annmax over time for crude trend analysis. DEFAULT: 1

months

Labels for the months. DEFAULT: J,F,M,A,M,J,J,A,S,O,N,D

xlab, ylab, zlab

Labels for the axes and title of colPointsLegend. Note that these are switched in plot 3 and 4. DEFAULT: Year, Month, substitute(values)

ylim

Limits of y axis. DEFAULT: NA (specified internally per plot type)

xaxs, yaxs

x and y Axis style, see par. DEFAULT: "r" (regular 4% expansion), "i" (internal range only)

main, adj

Graph title and offset to the left (adj passsed to title). DEFAULT: "Seasonality", 0.2

mar, mgp

Parameters specifying plot margin size and labels placement. DEFAULT: c(3,3,4,1), c(1.7,0.7,0) (Changed for plot 3:4 if not given)

keeppar

Logical: Keep the margin parameters? If FALSE, they are reset to the previous values. DEFAULT: TRUE

legargs

List of arguments passed as legargs to colPoints. DEFAULT: NULL (internally, plots 3:4 have density=F as default)

...

Further arguments passed to colPoints like pch, main, xaxs, but not Range (use vrange). Passed to spiralDate if plot=2, like add, format, lines.

Value

Data.frame with year, number of nonNA entries, max value + doy of annual maxima. Please note that the column year does not note the calendrical year if shift!=0.

See Also

spiralDate

Examples

browseURL("http://nrfa.ceh.ac.uk/data/station/meanflow/39072")
qfile <- system.file("extdata/discharge39072.csv", package="berryFunctions")
Q <- read.table(qfile, skip=19, header=TRUE, sep=",", fill=TRUE)[,1:2]
rm(qfile)
colnames(Q) <- c("date","discharge")
Q$date <- as.Date(Q$date)
Q$discharge[450:581] <- NA
plot(Q, type="l")
seas <- seasonality(date, discharge, data=Q, shift=100, main="NRFA: Thames\nRoyal Windsor Park")
head(seas)
# notice how n for nonmissing values is lower in one single hydrological year, 
# which includes parts of two consecutive calendarical years.
seas <- seasonality(date, discharge, data=Q, plot=2) # most floods in winter
seas <- seasonality(date, discharge, data=Q, plot=3)
seas <- seasonality(date, discharge, data=Q, plot=3, shift=100)
seasonality(date, discharge, data=Q[200:300,], plot=3, nmax=1)
seasonality(date, discharge, data=Q[100:200,], plot=3, nmax=1, shift=100)

## Not run: 
# dev.new(noRStudioGD=TRUE, record=TRUE)     # large graph on 2nd monitor
# par(mfrow=c(2,2))
# seas <- seasonality(date, discharge, data=Q, plot=1:4, shift=100)
# seas <- seasonality(date, discharge, data=Q, plot=1:4, lwd=2)
# seas <- seasonality(date, discharge, data=Q, plot=1:4, nmax=1, shift=100)
# seas <- seasonality(date, discharge, data=Q, plot=1:4, col=divPal(100, ryb=TRUE))
# ## End(Not run)