mapme.biodiversity (version 0.9.3)

gsw_recurrence: Calculate Global Surface Water (GSW) Recurrence

Description

Water Recurrence is a measurement of the degree of variability in the presence of water from year to year. It describes the frequency with which water returned to a particular location from one year to another, and is expressed as a percentage. The raster files have integer cell values between [0, 100], where 100 represents that water reoccurs predictably every year, whereas lower values indicate that water only occurs episodically.

Usage

calc_gsw_recurrence(engine = "extract", min_recurrence = NULL)

Value

A function that returns an indicator tibble with recurrence as variable and the corresponding area (in ha) as value.

Arguments

engine

The preferred processing functions from either one of "zonal", "extract" or "exactextract". Default: "extract".

min_recurrence

Threshold to define which pixels count towards the GSW recurrence area [0, 100].

Details

The raw data values are aggregated based on a provided threshold parameter min_recurrence, the function returns the area covered by values greater or equal than this threshold.

The required resources for this indicator are:

• global_surface_water_recurrence

Examples

# \dontshow{
mapme.biodiversity:::.copy_resource_dir(file.path(tempdir(), "mapme-data"))
# }
if (FALSE) {
library(sf)
library(mapme.biodiversity)

outdir <- file.path(tempdir(), "mapme-data")
dir.create(outdir, showWarnings = FALSE)

mapme_options(
  outdir = outdir,
  verbose = FALSE
)

aoi <- system.file("extdata", "shell_beach_protected_area_41057_B.gpkg",
  package = "mapme.biodiversity"
) %>%
  read_sf() %>%
  get_resources(get_global_surface_water_recurrence()) %>%
  calc_indicators(
    calc_gsw_recurrence(engine = "extract", min_recurrence = 10)
  ) %>%
  portfolio_long()

aoi
}