Find Neighbouring Cells

Given a vector of cell IDs (cell.ids) and a vector (blocks), which defines the number of blocks / cells per dimension, a list of all combinations of (linearly) neighbouring cells around each element of cell.ids is returned.

findLinearNeighbours(cell.ids, blocks, diag = FALSE)

Arguments

cell.ids	[integer] Vector of cell IDs (one number per cell) for which the neighbouring cells should be computed.
blocks	[integer] The number of blocks per dimension.
diag	[logical(1)] logical, indicating whether only cells that are located parallel to the axes should be considered (diag = FALSE) as neighbours. Alternatively, one can also look for neighbours that are located diagonally to a cell. The default is diag = FALSE.

Value

[list of integer(3)]. List of neighbours. Each list element stands for a combination of predecessing, current and succeeding cell.

Examples

cell.ids = c(5, 84, 17, 23)
blocks = c(5, 4, 7)

# (1) Considering diagonal neighbours as well:
findLinearNeighbours(cell.ids = cell.ids, blocks = blocks, diag = TRUE)
#> [[1]]
#> [1]  1 17 33
#> 
#> [[2]]
#> [1]  2 17 32
#> 
#> [[3]]
#> [1]  3 17 31
#> 
#> [[4]]
#> [1] 13 17 21
#> 
#> [[5]]
#> [1] 16 17 18
#> 
#> [[6]]
#> [1]  2 23 44
#> 
#> [[7]]
#> [1]  3 23 43
#> 
#> [[8]]
#> [1]  4 23 42
#> 
#> [[9]]
#> [1]  7 23 39
#> 
#> [[10]]
#> [1]  8 23 38
#> 
#> [[11]]
#> [1]  9 23 37
#> 
#> [[12]]
#> [1] 17 23 29
#> 
#> [[13]]
#> [1] 18 23 28
#> 
#> [[14]]
#> [1] 19 23 27
#> 
#> [[15]]
#> [1] 22 23 24
#> 
#> [[16]]
#> [1]  58  84 110
#> 
#> [[17]]
#> [1]  59  84 109
#> 
#> [[18]]
#> [1]  60  84 108
#> 
#> [[19]]
#> [1]  63  84 105
#> 
#> [[20]]
#> [1]  64  84 104
#> 
#> [[21]]
#> [1]  65  84 103
#> 
#> [[22]]
#> [1]  68  84 100
#> 
#> [[23]]
#> [1] 69 84 99
#> 
#> [[24]]
#> [1] 70 84 98
#> 
#> [[25]]
#> [1] 78 84 90
#> 
#> [[26]]
#> [1] 79 84 89
#> 
#> [[27]]
#> [1] 80 84 88
#> 
#> [[28]]
#> [1] 83 84 85
#> 

# (2) Only consider neighbours which are parellel to the axes:
findLinearNeighbours(cell.ids = cell.ids, blocks = blocks)
#> [[1]]
#> [1] 83 84 85
#> 
#> [[2]]
#> [1] 79 84 89
#> 
#> [[3]]
#> [1]  64  84 104
#> 
#> [[4]]
#> [1] 16 17 18
#> 
#> [[5]]
#> [1] 22 23 24
#> 
#> [[6]]
#> [1] 18 23 28
#> 
#> [[7]]
#> [1]  3 23 43
#>