Regulate a series using the constant value method

Transform an irregular time series in a regular time series, or fill gaps in regular time series using the constant value method

regconst(x, y=NULL, xmin=min(x), n=length(x),
        deltat=(max(x) - min(x))/(n - 1), rule=1, f=0)

Arguments

x: a vector with time in the irregular series. Missing values are allowed
y: a vector of same length as x and holding observations at corresponding times
xmin: allows to respecify the origin of time in the calculated regular time series. By default, the origin is not redefined and it is equivalent to the smallest value in x
n: the number of observations in the regular time series. By default, it is the same number than in the original irregular time series (i.e., length(x)
deltat: the time interval between two observations in the regulated time series
rule: the rule to use for extrapolated values (outside of the range in the initial irregular time series) in the regular time series. With rule=1 (by default), these entries are not calculated and get NA; with rule=2, these entries are extrapolated
f: coefficient giving more weight to the left value (f=0, by default), to the right value (f=) or to a combination of these two observations (0 < f <1)

Details

This is the simplest, but the less powerful regulation method. Interpolated values are calculated according to existing observations at left and at right as: x[reg] = x[right]*f + x[left]*(f-1), with 0 < f < 1.

Value

An object of type 'regul' is returned. It has methods print(), summary(), plot(), lines(), identify(), hist(), extract() and specs().

Author

Frédéric Ibanez (ibanez@obs-vlfr.fr), Philippe Grosjean (phgrosjean@sciviews.org)

Note

This function uses approx() for internal calculations

Examples

data(releve)
reg <- regconst(releve$Day, releve$Melosul)
plot(releve$Day, releve$Melosul, type="l")
lines(reg$x, reg$y, col=2)