adjust_envelope: adjust_envelope

In kongdd/gee_whittaker: Whittaker smoother

adjust_envelope

Description

Approach to upper envelope. This function works site by site.

Usage

adjust_envelope(
  t,
  y,
  z,
  w,
  QC_flag,
  type = "y",
  trs = 0.5,
  alpha = 0.02,
  wmin = 0.2
)

Arguments

t	Date object, corresponding date of y. If specified, yearly $ylu$ will be calculated, which is used to filter peak season.
y	Numeric vector, vegetation index time-series
w	(optional) Numeric vector, weights of y. If not specified, weights of all NA values will be wmin, the others will be 1.0.
QC_flag	Quality Control (QC) flag of original vegetation time-series y.
type	Character, ylu get by "y" or "z".
alpha	Double value in ⁠[0,1]⁠, quantile prob of ylu_min.
wmin	Double, minimum weight of bad points, which could be smaller the weight of snow, ice and cloud.
ylu	Numeric, lower and upper boundary of y.

Details

Smoothed time-series by Whittaker is often underestimated in the peak of growing season (abbreviated as peak season). In R, we can further constrain by yearly ylu. But, it's difficult to implement in GEE.

1. Not outlier.

2. In middle growing season.

3. only good values.

kongdd/gee_whittaker documentation built on April 14, 2024, 5:22 a.m.