Description Usage Arguments Value Author(s) See Also Examples

Extracts phenological metrics based on modelled NDVI values.

1 | ```
phenoPhase(x, phase, method, threshold, n)
``` |

`x` |
An object of class ‘NDVI’ containing modelled NDVI values. |

`phase` |
Determines which phase will be extracted: “ “ “ “ “ “ |

`method` |
Determines whether a global or local threshold is used for greenup and senescence extraction. “ “ |

`threshold` |
Threshold for local or global greenup/senescence-extraction method. Should have numerical value between ‘0’ and ‘1’. Global thresholds refer to a fix NDVI value independent of actual NDVI magnitudes. Local thresholds are based on (max - min) * e.g. 0.55. Hence, the respective NDVI value will vary dependent on e.g. land-cover. |

`n` |
The number ‘n’ of normal distributed values around the threshold for estimation of ‘sd’. The normal distribution uses the threshold as mean and a standaed deviation consisting of satellite error and standard deviation of fit residuals. The satellite error is considered as 0.02+0.02*value. |

A list containing the julian day of the year at which the phenologial phase occurs as list entry ‘mean’ and its standard deviation as list entry ‘sd’. The list contains vectors in ‘mean’ and ‘sd’ if multiple seasons are available in ‘NDVI’ object.

Daniel Doktor, Maximilian Lange

1 2 3 4 5 6 7 8 9 10 | ```
# load data
data(avhrr)
# create NDVI object, correct and model NDVI values
ndvi <- modelNDVI(ndvi.values=avhrr.ndvi/10000, year.int=1995,
correction="bise", method="LinIP", MARGIN=2,
doParallel=FALSE, slidingperiod=40)[[1]]
# extract greenup DOY
greenup <- phenoPhase(ndvi, phase="greenup", method="local", threshold=0.55, n=1000)
``` |

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