Convert a terra SpatRaster to a maxentcpp GridFloat — maxent_grid_from

Converts a single-layer terra::SpatRaster into a maxentcpp GridFloat external pointer. The raster must have exactly one layer and square cells (equal x and y resolution).

Usage

maxent_grid_from_terra(r, name = NULL)

Arguments

r: A single-layer terra::SpatRaster object.
name: Character: grid name (default: layer name from the raster).

Value

External pointer to a GridFloat C++ object.

Details

NA values in the raster are stored as NODATA (sentinel -9999).

Requires the terra package (listed in Suggests).

For the raster package, an equivalent workflow is:


  library(raster)
  r <- raster("bio1.tif")
  mat <- as.matrix(r)
  e <- extent(r)
  g <- maxent_grid_from_matrix(mat, xll = e@xmin, yll = e@ymin,
                               cellsize = res(r)[1],
                               name = names(r))

Examples

# \donttest{
if (requireNamespace("terra", quietly = TRUE)) {
  stack_path <- system.file("extdata", "stack_1_12_crop.rds",
                           package = "maxentcpp")
  r <- terra::unwrap(readRDS(stack_path))
  g <- maxent_grid_from_terra(r[[1]])
  maxent_grid_info(g)
}
#> $nrows
#> [1] 70
#> 
#> $ncols
#> [1] 99
#> 
#> $xll
#> [1] -99.5
#> 
#> $yll
#> [1] 10.66667
#> 
#> $cellsize
#> [1] 0.1666667
#> 
#> $nodata
#> [1] -9999
#> 
#> $name
#> [1] "bio1WH"
#> 
#> $count_data
#> [1] 2371
#> 
# }