I have a spatraster collection at 1-km resolution covering the entire globe. I want to split the spatraster into 6 (or any number) of equally sized spatraster
The below code splits the raster by layer but not spatially
library(terra)
s <- rast(system.file("ex/logo.tif", package="terra"))
s
class : SpatRaster
dimensions : 77, 101, 3 (nrow, ncol, nlyr)
resolution : 1, 1 (x, y)
extent : 0, 101, 0, 77 (xmin, xmax, ymin, ymax)
coord. ref. : Cartesian (Meter)
source : logo.tif
colors RGB : 1, 2, 3
names : red, green, blue
min values : 0, 0, 0
max values : 255, 255, 255
y <- terra::split(s, c(1,2,3))
y # 3 layers. But I want to split it spatially not by layer
You can use terra::makeTiles (or write your own loop that calls terra::crop).
For example, to split s in 6 tiles, you could do
# find the number or rows and columns of a tile
rc <- ceiling(dim(s)[1:2] / c(2,3))
rc
#[1] 39 34
# make tiles
x <- makeTiles(s, rc)
x
#[1] "tile_1.tif" "tile_2.tif" "tile_3.tif" "tile_4.tif" "tile_5.tif"
#[6] "tile_6.tif"
You can combine tiles with terra::vrt
v <- vrt(x)