cell2nb

0th

Percentile

Generate neighbours list for grid cells

The function generates a list of neighbours for a grid of cells. Helper functions are used to convert to and from the vector indices for row and column grid positions, and rook (shared edge) or queen (shared edge or vertex) neighbour definitions are applied by type. If torus is TRUE, the grid is mapped onto a torus, removing edge effects.

Keywords
spatial
Usage
cell2nb(nrow, ncol, type="rook", torus=FALSE) mrc2vi(rowcol, nrow, ncol) rookcell(rowcol, nrow, ncol, torus=FALSE, rmin=1, cmin=1) queencell(rowcol, nrow, ncol, torus=FALSE, rmin=1, cmin=1) vi2mrc(i, nrow, ncol)
Arguments
nrow
number of rows in the grid
ncol
number of columns in the grid
type
rook or queen
torus
map grid onto torus
rowcol
matrix with two columns of row, column indices
i
vector of vector indices corresponding to rowcol
rmin
lowest row index
cmin
lowset column index
Value

The function returns an object of class nb with a list of integer vectors containing neighbour region number ids. See card for details of “nb” objects.

See Also

summary.nb, card

Aliases
  • cell2nb
  • mrc2vi
  • rookcell
  • queencell
  • vi2mrc
Examples
nb7rt <- cell2nb(7, 7)
summary(nb7rt)
xyc <- attr(nb7rt, "region.id")
xy <- matrix(as.integer(unlist(strsplit(xyc, ":"))), ncol=2, byrow=TRUE)
plot(nb7rt, xy)
nb7rt <- cell2nb(7, 7, torus=TRUE)
summary(nb7rt)
Documentation reproduced from package spdep, version 0.6-9, License: GPL (>= 2)

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