divraster (version 1.2.3)

combine.rasters: Combine GeoTIFF rasters into a multilayer SpatRaster

Description

Reads GeoTIFF files from a directory OR combines already-loaded SpatRasters. Computes the union of their extents, resamples them to a common grid, and returns a single multilayer SpatRaster.

Usage

combine.rasters(
  raster_list = NULL,
  dir_path = NULL,
  pattern = NULL,
  method = "bilinear"
)

Value

A single multilayer SpatRaster with one layer per input. Layers are named from list names or file basenames without extension.

Arguments

raster_list

Optional list of SpatRaster objects already loaded in R. If provided, dir_path and pattern are ignored.

dir_path

Character. Directory containing input GeoTIFF files. Only used if raster_list is NULL.

pattern

Character. Pattern that file names must contain. Only used if raster_list is NULL.

method

Character. Resampling method passed to terra::resample(), e.g. "bilinear" (default) or "near" for categorical data.

Details

The first raster (file or list element) defines the target resolution, origin and CRS; the union of all extents defines the spatial coverage. Areas where a raster has no data are filled with NA.

Examples

# \donttest{
library(terra)

# Create 3 separate rasters with different extents
r1 <- rast(ncol = 30, nrow = 30, xmin = 0, xmax = 10,
           ymin = 0, ymax = 10)
values(r1) <- runif(ncell(r1), 0, 100)
crs(r1) <- "+proj=longlat +datum=WGS84 +no_defs"

r2 <- rast(ncol = 30, nrow = 30, xmin = 1, xmax = 11,
           ymin = 1, ymax = 11)
values(r2) <- runif(ncell(r2), 0, 100)
crs(r2) <- crs(r1)

r3 <- rast(ncol = 30, nrow = 30, xmin = -1, xmax = 9,
           ymin = -1, ymax = 9)
values(r3) <- runif(ncell(r3), 0, 100)
crs(r3) <- crs(r1)

# Combine into single multilayer SpatRaster
raster_list <- list(baseline = r1, future_A = r2, future_B = r3)
combined <- combine.rasters(raster_list = raster_list)
combined
# }