calculate_WDI {wdiEF} | R Documentation |
Calculate the Water Deficit Index (WDI)
Description
This function calculates the WDI from two rasters: fractional vegetation cover (FVC) and the surface-air temperature difference (TS-TA). It saves the resulting WDI raster to the specified output path.
Usage
calculate_WDI(
FVC_path,
TS_TA_path,
output_path,
n_intervals = 20,
percentile = 0.01
)
Arguments
FVC_path |
Character. File path to the FVC raster.Must have the same CRS and extent as the TS-TA raster. |
TS_TA_path |
Character. File path to the raster of TS-TA (surface-air temperature difference). TS and TA must have the same unit of measurement (Kelvin preferably). |
output_path |
Character. File path where the WDI raster will be saved. |
n_intervals |
Integer. Number of intervals for splitting FVC values (default: 20). |
percentile |
Numeric. Percentage used for identifying wet and dry edges (default: 0.01). |
Details
The input rasters (
FVC
andTS-TA
) must have the same CRS (Coordinate Reference System) and extent.If they differ, the function will attempt to reproject and resample the rasters automatically.
Value
A raster object representing the Water Deficit Index (WDI).
Examples
# Paths to example data included in the package
library(terra)
FVC_raster <- rast(system.file("extdata", "FVC_reduced.tif", package = "wdiEF"))
TS_TA_raster <- rast(system.file("extdata", "TS_TA_reduced.tif", package = "wdiEF"))
# Output path (temporary file for example purposes)
output_path <- tempfile(fileext = ".tif")
# Run the function
calculate_WDI(
FVC_path = FVC_raster,
TS_TA_path = TS_TA_raster,
output_path = output_path,
n_intervals = 20,
percentile = 0.01
)
# Print the output path
print(output_path)