filter_top | R Documentation |
Using upper quantile (default = 0.925) of multi-year MODIS data, determine the top NDVI for each id.
filter_top(DT, probs = 0.925, id = "id")
DT |
data.table of NDVI time series |
probs |
quantile probability to determine top. default is 0.925. |
id |
id column. default is 'id'. See details. |
The id argument is used to split between sampling units. This may be a point id, polygon id, pixel id, etc. depending on your analysis.
filtered data.table with appended 'top' column of each id's top (quantile) NDVI value.
Other filter:
filter_ndvi()
,
filter_qa()
,
filter_roll()
,
filter_winter()
# Load data.table
library(data.table)
# Read example data
ndvi <- fread(system.file("extdata", "sampled-ndvi-MODIS-MOD13Q1.csv", package = "irg"))
filter_qa(ndvi, ndvi = 'NDVI', qa = 'SummaryQA', good = c(0, 1))
filter_winter(ndvi, probs = 0.025, limits = c(60L, 300L), doy = 'DayOfYear', id = 'id')
filter_roll(ndvi, window = 3L, id = 'id')
filter_top(ndvi, probs = 0.925, id = 'id')
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