"sts" ObjectsAdd a nicely formatted x-axis to time series plots related to the
"sts" class. This utility function is, e.g., used
by stsplot_time1 and plotHHH4_fitted1.
addFormattedXAxis(x, epochsAsDate = FALSE,
xaxis.tickFreq = list("%Q"=atChange),
xaxis.labelFreq = xaxis.tickFreq,
xaxis.labelFormat = "%G\n\n%OQ",
...)NULL (invisibly). The function is called for its side effects.
an object of class "sts".
a logical indicating if the old (FALSE) or the new
(TRUE) and more flexible implementation should be used.
The xaxis.* arguments are only relevant for the new
implementation epochsAsDate = TRUE.
see the details below.
further arguments passed to axis.
Michael Höhle with contributions by Sebastian Meyer
The setting epochsAsDate = TRUE
enables very flexible formatting of the x-axis and its
annotations using the xaxis.tickFreq, xaxis.labelFreq
and xaxis.labelFormat arguments. The first two are named lists containing
pairs with the name being a strftime single
conversion specification and the second part is a function which based
on this conversion returns a subset of the rows in the sts
objects. The subsetting function has the following header:
function(x,xm1), where x is a vector containing
the result of applying the conversion in name to the epochs of
the sts object and xm1 is the scalar result when
applying the conversion to the natural element just before the first
epoch. Please note that the input to the subsetting function is converted
using as.numeric before calling the function. Hence, the
conversion specification needs to result in a string convertible to integer.
Three predefined subsetting functions exist:
atChange, at2ndChange and atMedian, which
are used to make a tick at each (each 2nd for at2ndChange)
change and at the median index computed on all having the same value,
respectively:
atChange <- function(x,xm1) which(diff(c(xm1,x)) != 0)
at2ndChange <- function(x,xm1) which(diff(c(xm1,x) %/% 2) != 0)
atMedian <- function(x,xm1) tapply(seq_along(x), INDEX=x, quantile, prob=0.5, type=3)
By defining own functions here, one can obtain an arbitrary degree of flexibility.
Finally, xaxis.labelFormat is a strftime
compatible formatting string., e.g. the default value is
"%G\n\n%OQ", which means ISO year and quarter (in roman
letters) stacked on top of each other.
the examples in stsplot_time1 and plotHHH4_fitted1