wdiEF Package

The wdiEF package provides tools to calculate the Water Deficit Index (WDI) and the Evaporative Fraction (EF) from raster data. It utilizes fractional vegetation cover (FVC) and surface-air temperature difference (TS-TA) to generate the WDI or EF raster.

Installation

You can install the development version of wdiEF directly from your local folder:

Requirements

• The input rasters (TS and TA) must have the same unit of measurement (Kelvin preferably) to ensure accurate calculations of TS-TA and the Water Deficit Index (WDI) or the Evaporative Fraction (EF).

• The input rasters (FVC and TS-TA) must:

  • Have the same Coordinate Reference System (CRS).
  • Cover the same geographic extent.

• If these conditions are not met, the function attempt to align the rasters automatically (with warnings).

Dependencies

The wdiEF package automatically manages the following dependencies: - terra for raster manipulation. - dplyr for data manipulation. - stats for statistical calculations.

You do not need to load these packages manually; they are handled internally by wdiEF

Examples Usage of the wdiEF Package

To use the wdiEF package, start by loading the necessary library in R.

• Define the paths to the input files (FVC and TS-TA rasters) and the output path for the calculated WDI raster.

  Load the necessary package

  library(wdiEF)

  Input raster paths

  FVC_path <- "path/to/FVC.tif" TS_TA_path <- "path/to/TS_TA.tif"

  Output raster path

  output_path <- "path/to/WDI.tif"

  Calculate WDI

  calculate_WDI( FVC_path = FVC_path, TS_TA_path = TS_TA_path, output_path = output_path, n_intervals = 20, percentile = 0.01 )

  Check the output

  WDI <- terra::rast(output_path) plot(WDI)

• Define the paths to the input files (FVC and TS-TA rasters) and

the output path for the calculated EF raster.

# Load the necessary package
library(wdiEF)

# Input raster paths
FVC_path <- "path/to/FVC.tif"
TS_TA_path <- "path/to/TS_TA.tif"

# Output raster path
output_path <- "path/to/EF.tif"

# Calculate EF
calculate_EF(
  FVC_path = FVC_path,
  TS_TA_path = TS_TA_path,
  output_path = output_path,
  n_intervals = 20,
  percentile = 0.01
)

# Check the output
EF <- terra::rast(output_path)
plot(EF)