Organize tiles from a tilePlan into hierarchical groups for batch processing. Groups can represent spatial regions, processing stages, or any logical organization of tiles.
Usage
tileGroup(tp, groups = list())See also
Other tile orchestration:
iterSplit(),
tileGroup-class,
tileIterator,
tileIterator-class
Examples
tp <- tilePlan("spatial")
ext(tp) <- c(0, 100, 0, 100)
length(tp) <- 16
# Create groups
tg <- tileGroup(tp, groups = list(
"g1" = 1:4, # vector indexing
"g2" = list(2, 1:4), # ij indexing
"g3" = list(2:4, 1:2) # selection overlaps are allowed
# (not all tiles need to be selected)
))
# length() returns number of groups
length(tg)
#> [1] 3
# Get group bounds:
tg[, "g1"] # first 4
#> [[1]]
#> SpatExtent : 0, 25, 0, 25 (xmin, xmax, ymin, ymax)
#>
#> [[2]]
#> SpatExtent : 25, 50, 0, 25 (xmin, xmax, ymin, ymax)
#>
#> [[3]]
#> SpatExtent : 50, 75, 0, 25 (xmin, xmax, ymin, ymax)
#>
#> [[4]]
#> SpatExtent : 75, 100, 0, 25 (xmin, xmax, ymin, ymax)
#>
tg[, "g2"] # next 4
#> [[1]]
#> SpatExtent : 0, 25, 25, 50 (xmin, xmax, ymin, ymax)
#>
#> [[2]]
#> SpatExtent : 25, 50, 25, 50 (xmin, xmax, ymin, ymax)
#>
#> [[3]]
#> SpatExtent : 50, 75, 25, 50 (xmin, xmax, ymin, ymax)
#>
#> [[4]]
#> SpatExtent : 75, 100, 25, 50 (xmin, xmax, ymin, ymax)
#>
tg[, "g3"] # specific 6
#> [[1]]
#> SpatExtent : 0, 25, 25, 50 (xmin, xmax, ymin, ymax)
#>
#> [[2]]
#> SpatExtent : 25, 50, 25, 50 (xmin, xmax, ymin, ymax)
#>
#> [[3]]
#> SpatExtent : 0, 25, 50, 75 (xmin, xmax, ymin, ymax)
#>
#> [[4]]
#> SpatExtent : 25, 50, 50, 75 (xmin, xmax, ymin, ymax)
#>
#> [[5]]
#> SpatExtent : 0, 25, 75, 100 (xmin, xmax, ymin, ymax)
#>
#> [[6]]
#> SpatExtent : 25, 50, 75, 100 (xmin, xmax, ymin, ymax)
#>
# not recommended for large groups
tg[c(3, 1), "g3"] # get nth item in group
#> [[1]]
#> SpatExtent : 0, 25, 50, 75 (xmin, xmax, ymin, ymax)
#>
#> [[2]]
#> SpatExtent : 0, 25, 25, 50 (xmin, xmax, ymin, ymax)
#>
# Set active group for shorthand indexing
tg$active <- "g1"
# length() is based on group length when active is set
length(tg)
#> [1] 4
tg[2] # Position 2 from g1
#> [[1]]
#> SpatExtent : 25, 50, 0, 25 (xmin, xmax, ymin, ymax)
#>
# iterator can be created when active group is set
iter <- tileIterator(tg, batch_size = 2)
iter$next_batch()
#> [[1]]
#> SpatExtent : 0, 25, 0, 25 (xmin, xmax, ymin, ymax)
#>
#> [[2]]
#> SpatExtent : 25, 50, 0, 25 (xmin, xmax, ymin, ymax)
#>
#> attr(,"batch_start")
#> [1] 1
#> attr(,"batch_end")
#> [1] 2
#> attr(,"batch_size")
#> [1] 2
#> attr(,"iterator_position")
#> [1] 2
iter$next_batch()
#> [[1]]
#> SpatExtent : 50, 75, 0, 25 (xmin, xmax, ymin, ymax)
#>
#> [[2]]
#> SpatExtent : 75, 100, 0, 25 (xmin, xmax, ymin, ymax)
#>
#> attr(,"batch_start")
#> [1] 3
#> attr(,"batch_end")
#> [1] 4
#> attr(,"batch_size")
#> [1] 2
#> attr(,"iterator_position")
#> [1] 4
iter$next_batch() # no more items
#> list()
tg$active <- NULL # Clear active group by setting NULL