has_peaks: Test whether a phases has a peak.

In Issoufou-Liman/growingSeason: Estimating growing season metrics from seasonal data

Description

Takes a vector and returns a list containing the indices of one or more peaks and TRUE as test if it found a peak. if no peak is found, then has_peaks () will returned null as peak and set the test to FALSE. Applied to phases slot of the phases object (see ?phases) this function can help to determine whether a phase qualifies for a season or not. Note that a season is a phases having a peak.

Usage

has_peaks(x, npeaks = 1, steps = 2)

Arguments

x	A numeric vector on which to test the existance of one or more peaks
npeaks	An integer specifying the number of peaks to look for.
steps	An interger specifying the number of points for a given points to qualify for a peak.

Details

has_peaks () extends get_falls () in the sense that it just internally applies get_falls () function to - x to locate the peaks and add the logical test.

Value

a list containing of the indices of the peaks and logical test.

Author(s)

Issoufou Liman

See Also

get_falls

Examples

## data with complete cases
nam<- seq.Date(from = as.Date('2016-01-01'), to = as.Date ('2018-12-31'), by = 16)
dy11 <- c(1.40, 1.00, 1.50, 2.00, 5.00, 3.00, 1.00, 0.76, 2.00, 1.00, 3.50, 3.00, 1.50)
dy12 <- c(1.30, 1.10, 1.40, 2.01, 5.50, 2.80, 1.01, 1, 2.03, 1.09, 3.10, 3.00, 1.50)
dy1 <- c(dy11, dy12)
names(dy1) <- nam[1:length(dy1)]

default_par <- par(no.readonly=TRUE)
layout(rbind(c(1, 1), c(2, 3)))
par(mar = c(2, 2, 1, 1))
plot (dy1, type = 'o')
y <- phases (dy1, ts_freq = 12)
y <- y$phases
lapply (y, has_peaks)
lapply (y, plot, type = 'o')


## data with manageable number of NAs
dy2 <- dy1
dy2[23:length(dy2)] <- NA

plot (dy2, type = 'o')
y <- phases (dy2, ts_freq = 12)
y <- y$phases
lapply (y, has_peaks)
lapply (y, plot, type = 'o')


## data with unmanageable number of NAs. This does not make sense as a season!
dy3 <- dy1
dy3[13:20] <- NA

plot (dy3, type = 'o')
y <- phases (dy3, ts_freq = 12)
y <- y$phases
lapply (y, has_peaks)
lapply (y, plot, type = 'o')
par(default_par)

Issoufou-Liman/growingSeason documentation built on Jan. 23, 2020, 3:43 a.m.