phenofit (version 0.3.9)

PhenoKl: Phenology extraction in Inflection method (Zhang)

Description

Phenology extraction in Inflection method (Zhang)

Usage

PhenoKl(
  fFIT,
  t = NULL,
  analytical = FALSE,
  smoothed.spline = FALSE,
  IsPlot = TRUE,
  show.legend = TRUE,
  ...
)

Value

A numeric vector, with the elements of: Greenup, Maturity, Senescence, Dormancy.

Arguments

fFIT

object return by curvefit()

t

doy vector, corresponding doy of vegetation index.

analytical

If true, numDeriv package grad and hess will be used; if false, D1 and D2 will be used.

smoothed.spline

Whether apply smooth.spline first?

IsPlot

whether to plot?

show.legend

whether show figure lelend?

...

Other parameters will be ignored.

References

1. Zhang, X., Friedl, M. A., Schaaf, C. B., Strahler, A. H., Hodges, J. C. F. F., Gao, F., … Huete, A. (2003). Monitoring vegetation phenology using MODIS. Remote Sensing of Environment, 84(3), 471–475. tools:::Rd_expr_doi("10.1016/S0034-4257(02)00135-9")

Examples

# `doubleLog.Beck` simulate vegetation time-series
t    <- seq(1, 365, 8)
tout <- seq(1, 365, 1)
par  = c( mn  = 0.1 , mx  = 0.7 , sos = 50 , rsp = 0.1 , eos = 250, rau = 0.1)
y <- doubleLog.Beck(par, t)

methods <- c("AG", "Beck", "Elmore", "Gu", "Zhang") # "Klos" too slow
fit <- curvefit(y, t, tout, methods)
x <- fit$model$AG # one model

par(mfrow = c(2, 2))
PhenoTrs(x)
PhenoDeriv(x)
PhenoGu(x)
PhenoKl(x)