Sort raster layers by name using natural ordering — sort_raster

Sorts the layers of a terra::SpatRaster according to their layer names using natural (mixed) ordering. Numeric components of layer names are ordered numerically rather than lexicographically (e.g. "layer2" is placed before "layer10").

Usage

sort_raster_layers(r)

Arguments

r: A terra::SpatRaster.

Value

A terra::SpatRaster with layers reordered according to natural sorting of layer names.

Details

If duplicate layer names are detected, a warning is issued because the resulting order of layers with identical names cannot be distinguished by name alone. Layer order is preserved among duplicated names according to their original positions.

Author

Ahmed El-Gabbas

Examples

ecokit::load_packages(terra, dplyr, dismo)

fnames <- list.files(
  path = paste(system.file(package = "dismo"), "/ex", sep = ""),
  pattern = "grd", full.names = TRUE)
(r <- terra::rast(fnames))
#> class       : SpatRaster
#> size        : 192, 186, 9  (nrow, ncol, nlyr)
#> resolution  : 0.5, 0.5  (x, y)
#> extent      : -125, -32, -56, 40  (xmin, xmax, ymin, ymax)
#> coord. ref. : +proj=longlat +ellps=WGS84 +towgs84=0,0,0,0,0,0,0 +no_defs
#> sources     : bio1.grd
#>               bio12.grd
#>               bio16.grd
#>               ... and 6 more sources
#> names       : bio1, bio12, bio16, bio17, bio5, bio6, ...
#> min values  :  -23,     0,     0,     0,   61, -212, ...
#> max values  :  289,  7682,  2458,  1496,  422,  242, ...
names(r)
#> [1] "bio1"  "bio12" "bio16" "bio17" "bio5"  "bio6"  "bio7"  "bio8"  "biome"

(r2 <- sort_raster_layers(r))
#> class       : SpatRaster
#> size        : 192, 186, 9  (nrow, ncol, nlyr)
#> resolution  : 0.5, 0.5  (x, y)
#> extent      : -125, -32, -56, 40  (xmin, xmax, ymin, ymax)
#> coord. ref. : +proj=longlat +ellps=WGS84 +towgs84=0,0,0,0,0,0,0 +no_defs
#> sources     : bio1.grd
#>               bio5.grd
#>               bio6.grd
#>               ... and 6 more sources
#> names       : bio1, bio5, bio6, bio7, bio8, bio12, ...
#> min values  :  -23,   61, -212,   60,  -66,     0, ...
#> max values  :  289,  422,  242,  461,  323,  7682, ...
names(r2)
#> [1] "bio1"  "bio5"  "bio6"  "bio7"  "bio8"  "bio12" "bio16" "bio17" "biome"

# ---------------------------------------------------

r <- terra::rast(nrows = 10, ncols = 10, nlyrs = 4, vals = 1) %>%
   stats::setNames(c("layer10", "layer2", "layer10", "layer1"))
r
#> class       : SpatRaster
#> size        : 10, 10, 4  (nrow, ncol, nlyr)
#> resolution  : 36, 18  (x, y)
#> extent      : -180, 180, -90, 90  (xmin, xmax, ymin, ymax)
#> coord. ref. : lon/lat WGS 84 (CRS84) (OGC:CRS84)
#> source      : spat_23906074585d_9104_BnO3HOrWuPceBcV.tif
#> names       : layer10, layer2, layer10, layer1
#> min values  :       1,      1,       1,      1
#> max values  :       1,      1,       1,      1

sort_raster_layers(r)
#> Warning: Duplicated layer names detected: 'layer10'. Layers will be sorted by name, but duplicated names cannot be uniquely distinguished.
#> class       : SpatRaster
#> size        : 10, 10, 4  (nrow, ncol, nlyr)
#> resolution  : 36, 18  (x, y)
#> extent      : -180, 180, -90, 90  (xmin, xmax, ymin, ymax)
#> coord. ref. : lon/lat WGS 84 (CRS84) (OGC:CRS84)
#> source      : spat_23906074585d_9104_BnO3HOrWuPceBcV.tif
#> names       : layer1, layer2, layer10, layer10
#> min values  :      1,      1,       1,       1
#> max values  :      1,      1,       1,       1