R: Identify if a gap in a time series occurs permanently

IsPermanentGap {greenbrown}

R Documentation

Identify if a gap in a time series occurs permanently

Description

The function identifies obervations in time series as permanent gaps if the gap occurs during the same period in several years.

Usage

IsPermanentGap(Yt, min.gapfrac = 0.2, lower = TRUE, ...)

Arguments

`Yt`	univariate time series of class `ts`
`min.gapfrac`	How often has an observation to be NA to be considered as a permanent gap? (fraction of time series length) Example: If the month January is 5 times NA in a 10 year time series (= 0.5), then the month January is considered as permanent gap if min.gapfrac = 0.4.
`lower`	identify lower gaps (TRUE), upper gaps (FALSE) or lower and upper gaps (NULL)
`...`	further arguments (currently not used)

Author(s)

Matthias Forkel <matthias.forkel@geo.tuwien.ac.at> [aut, cre]

Examples

# load NDVI data
data(ndvi)

# introduce some systematic gaps in january, february, december and july
gaps <- ndvi
winter <- cycle(ndvi) == 1 | cycle(ndvi) == 2 | cycle(ndvi) == 12 | cycle(ndvi) == 7
gaps[winter] <- NA
gaps[1] <- 0.2
gaps[7] <- 0.3
plot(gaps)

# identifiy permanent winter gaps only
IsPermanentGap(gaps, lower=TRUE)

# identify permanent summer gaps
IsPermanentGap(gaps, lower=FALSE)

# identify all permanent gaps
IsPermanentGap(gaps, lower=NULL)