Pure index arithmetic: how many tiles fit and what their extents are.
Tiles are enumerated left to right, then top to bottom, matching cell
order. Edge tiles may be smaller than tile_dim. Every tile is aligned
to the parent and grid_offset() of a tile is its origin in parent
cells.
Usage
grid_tiles(dimension, extent = NULL, tile_dim = c(256L, 256L))
Arguments
- dimension
integer ncol, nrow
- extent
numeric extent xmin,xmax,ymin,ymax
- tile_dim
tile dimension (ncol, nrow), recycled if length 1
Value
list of lists, each with dimension and extent, plus
offset (the tile's 0-based c(col, row) origin in the parent)
Examples
tl <- grid_tiles(c(10L, 7L), c(0, 10, 0, 7), c(4L, 4L))
length(tl)
#> [1] 6
tl[[6]]
#> $dimension
#> [1] 2 3
#>
#> $extent
#> [1] 8 10 0 3
#>
#> $offset
#> col row
#> 8 4
#>