Extract Remote Sensing Vegetation Phenology
Weighted HANTS SMOOTH
Weighted Savitzky-Golay
Weigthed Whittaker Smoother
tidy_MOD13
tidy_pheno
V-curve theory to optimize Whittaker parameter lambda.
Weight updating functions
Weighted Whittaker smoothing with a second order finite difference pen...
Goal function of fine curve fitting methods
objective function of double logistics
S3 class of fine curve fitting object.
S3 class of multiple fine curve fittings object.
find_season
get_pheno
getRealDate
GOF
Interface of unified optimization functions.
Initial lambda value of Whittaker smoother
init_param
skewness and kurtosis
lambda_vcurve
Double logistics in Rcpp
Phenology extraction in Threshold method (TRS)
plot_curvefits
Plot INPUT returned by check_input
plot_phenofit
plot_season
Extract Vegetation Phenology at site scale
divide_seasons
qc level, color and shape
Initial weights for sentinel2 according to SCL band
Add one year data in the head and tail
get rough fitting
Check growing season head and tail minimum values
check_input
check_ylu
Fine curve fitting
curvefit0
curvefits by local model functions of TIMESAT
Fine Curve fitting
cutoff
weighted CV
D
findpeaks
Fine fitting
getFittings
get_GOF
Get parameters from curve fitting result
Fine fitting functions
melt_list
movmean
Unified optimization function
optim_pheno
Phenology extraction in Derivative method (DER)
phenofit
Phenology extraction in GU method (GU)
Phenology extraction in Inflection method (Zhang)
Initial weights according to qc
Critical value of determined correlation
season_filter
Weighted Savitzky-Golay written in RcppArmadillo
Objects exported from other packages
rm too closed peaks or troughs
Rough fitting
Growing season division (unstable version)
Moving growing season division
Growing season division
set and get phenofit option
The merits of 'TIMESAT' and 'phenopix' are adopted. Besides, a simple and growing season dividing method and a practical snow elimination method based on Whittaker were proposed. 7 curve fitting methods and 4 phenology extraction methods were provided. Parameters boundary are considered for every curve fitting methods according to their ecological meaning. And 'optimx' is used to select best optimization method for different curve fitting methods. Reference: Kong, D., (2020). R package: A state-of-the-art Vegetation Phenology extraction package, phenofit version 0.3.1, <doi:10.5281/zenodo.5150204>; Kong, D., Zhang, Y., Wang, D., Chen, J., & Gu, X. (2020). Photoperiod Explains the Asynchronization Between Vegetation Carbon Phenology and Vegetation Greenness Phenology. Journal of Geophysical Research: Biogeosciences, 125(8), e2020JG005636. <doi:10.1029/2020JG005636>; Kong, D., Zhang, Y., Gu, X., & Wang, D. (2019). A robust method for reconstructing global MODIS EVI time series on the Google Earth Engine. ISPRS Journal of Photogrammetry and Remote Sensing, 155, 13–24; Zhang, Q., Kong, D., Shi, P., Singh, V.P., Sun, P., 2018. Vegetation phenology on the Qinghai-Tibetan Plateau and its response to climate change (1982–2013). Agric. For. Meteorol. 248, 408–417. <doi:10.1016/j.agrformet.2017.10.026>.