Remove deforested plots by overlaying plots with Global Forest Change data

This function identifies and removes plots that have been deforested based on the Global Forest Change (GFC) dataset (Hansen et al., 2013). It processes each plot, downloads the necessary forest loss tiles, and determines if the plot has been deforested beyond a set deforestation threshold or if the deforestation occurred before or during the specified map year.

Usage

Deforested(
  plt,
  map_year,
  gfc_folder = "data/GFC",
  gfc_dataset_year = "latest",
  defo_threshold = 0.05
)

Arguments

plt: A data frame or sf object containing plot data. For data frame input format, longitude and latitude coordinates should be placed under "POINT_X" and "POINT_Y" columns respectively in WGS 84 CRS.
map_year: Numeric value indicating the threshold year for deforestation. Plots with deforestation started at or before the map_year will be removed from the $non_deforested_plots list element output. Any year in the 2001-2023 range.
gfc_folder: Character string specifying the directory to download GFC data.
gfc_dataset_year: Numeric value describing which version of the Hansen data to use: any year in the 2018-2023 range or "latest" (default).
defo_threshold: Numeric value indicating the deforestation threshold. Plots with a deforestation area proportion larger than the set defo_threshold will be removed from the $non_deforested_plots list element output. Default is 5%.

Value

A list containing two elements:

non_deforested_plots: A sf object with non-deforested plots
all_plots: The original input sf object with added deforestated proportion (0-1) w.r.t. to plot area and deforestation start year

References

M. C. Hansen et al., High-Resolution Global Maps of 21st-Century Forest Cover Change. Science342,850-853(2013). DOI:10.1126/science.1244693

Examples

if (FALSE) { # \dontrun{
# 4 plots without and 4 plots with deforestation:
plots_sample <- c(1, 2, 3, 4, 182, 200, 323, 6765)
sampled_plots <- plots[plots_sample,]
Deforested(sampled_plots, 2010)
} # }