A useful workflow for raster data in a memory bounded environment is to
chunk a grid into sections or tiles. These functions compute tiles
suitable for such processing. Use grd_tile_summary() to generate
statistics for level values to choose for your application.
grd_tile_template(grid, level)
grd_tile_summary(grid, levels = NULL)A grd_xy(), grd_rct(), or other object
implementing grd_*() methods.
An integer describing the overview level. This is related to
the step value by a power of 2 (i.e., a level of 1 indicates a step of
2, a level of 2 indicates a step of 4, etc.).
A vector of level values or NULL to use a sequence from
0 to the level that would result in a 1 x 1 grid.
A grd()
grid <- grd_rct(volcano)
grd_tile_summary(grid)
#> level xmin ymin xmax ymax nx ny dx dy width height
#> 1 0 0 0 61 87 61 87 1 1 61 87
#> 2 1 0 -1 62 87 31 44 2 2 62 88
#> 3 2 0 -1 64 87 16 22 4 4 64 88
#> 4 3 0 -1 64 87 8 11 8 8 64 88
#> 5 4 0 -9 64 87 4 6 16 16 64 96
#> 6 5 0 -9 64 87 2 3 32 32 64 96
#> 7 6 0 -41 64 87 1 2 64 64 64 128
#> 8 7 0 -41 64 87 1 1 64 128 64 128
grd_tile_template(grid, 3)
#> <wk_grd_rct [11 x 8 x 0] => [0 -1 64 87]>
#> List of 2
#> $ data: logi[1:11, 1:8, 0 ]
#> $ bbox: wk_rct[1:1] [0 -1 64 87]
#> - attr(*, "class")= chr [1:2] "wk_grd_rct" "wk_grd"