monthplot Plot a Seasonal or other Subseries from a Time Series

Description

These functions plot seasonal (or other) subseries of a time series. For each season (or other category), a time series is plotted.

Usage

monthplot(x, ...)

## S3 method for class 'stl'
monthplot(x, labels = NULL, ylab = choice, choice = "seasonal",
          ...)

## S3 method for class 'StructTS'
monthplot(x, labels = NULL, ylab = choice, choice = "sea", ...)

## S3 method for class 'ts'
monthplot(x, labels = NULL, times = time(x), phase = cycle(x),
             ylab = deparse1(substitute(x)), ...)

## Default S3 method:
monthplot(x, labels = 1L:12L,
          ylab = deparse1(substitute(x)),
          times = seq_along(x),
          phase = (times - 1L)%%length(labels) + 1L, base = mean,
          axes = TRUE, type = c("l", "h"), box = TRUE,
          add = FALSE,
          col = par("col"), lty = par("lty"), lwd = par("lwd"),
          col.base = col, lty.base = lty, lwd.base = lwd, ...)

Arguments

x	Time series or related object.
labels	Labels to use for each ‘season’.
ylab	y label.
times	Time of each observation.
phase	Indicator for each ‘season’.
base	Function to use for reference line for subseries.
choice	Which series of an stl or StructTS object?
...	Arguments to be passed to the default method or graphical parameters.
axes	Should axes be drawn (ignored if add = TRUE)?
type	Type of plot. The default is to join the points with lines, and "h" is for histogram-like vertical lines.
box	Should a box be drawn (ignored if add = TRUE)?
add	Should thus just add on an existing plot.
col, lty, lwd	Graphics parameters for the series.
col.base, lty.base, lwd.base	Graphics parameters for the segments used for the reference lines.

Details

These functions extract subseries from a time series and plot them all in one frame. The ts, stl, and StructTS methods use the internally recorded frequency and start and finish times to set the scale and the seasons. The default method assumes observations come in groups of 12 (though this can be changed).

If the labels are not given but the phase is given, then the labels default to the unique values of the phase. If both are given, then the phase values are assumed to be indices into the labels array, i.e., they should be in the range from 1 to length(labels).

Value

These functions are executed for their side effect of drawing a seasonal subseries plot on the current graphical window.

Author(s)

Duncan Murdoch

References

Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.

See Also

ts, stl, StructTS

Examples

require(graphics)

## The CO2 data
fit <- stl(log(co2), s.window = 20, t.window = 20)
plot(fit)
op <- par(mfrow = c(2,2))
monthplot(co2, ylab = "data", cex.axis = 0.8)
monthplot(fit, choice = "seasonal", cex.axis = 0.8)
monthplot(fit, choice = "trend", cex.axis = 0.8)
monthplot(fit, choice = "remainder", type = "h", cex.axis = 0.8)
par(op)

## The CO2 data, grouped quarterly
quarter <- (cycle(co2) - 1) %/% 3
monthplot(co2, phase = quarter)

## see also JohnsonJohnson