Scale DOY

Scale the day of the year to 0-1 (like NDVI).

scale_doy(DT, doy = "DayOfYear")

Arguments

DT

data.table of NDVI time series

doy

julian day column. default is 'DayOfYear'.

Value

data.table with appended 't' column of 0-1 scaled day of year.

See also

Other scale: scale_ndvi()

Examples

# Load data.table
library(data.table)

# Read in example data
ndvi <- fread(system.file("extdata", "sampled-ndvi-MODIS-MOD13Q1.csv", package = "irg"))

# Scale DOY
scale_doy(ndvi)
#>         id   NDVI SummaryQA DayOfYear    yr           t
#>      <int>  <num>     <num>     <num> <num>       <num>
#>   1:     0 0.1864         3        11  2015 0.027397260
#>   2:     1 0.0541         2         3  2015 0.005479452
#>   3:     2 0.1781         3        11  2015 0.027397260
#>   4:     3 0.1024         2         5  2015 0.010958904
#>   5:     4 0.0898         2         3  2015 0.005479452
#>  ---                                                   
#> 801:     2 0.1179         2       364  2019 0.994520548
#> 802:     3 0.0789         2       364  2019 0.994520548
#> 803:     4 0.1572         2       364  2019 0.994520548
#> 804:     5 0.0763         2       364  2019 0.994520548
#> 805:     6 0.1197         2       362  2019 0.989041096