gridindex2nb function

create neighbourhood (nb) object from grid geometry

gridIndex2nb(obj, maxdist = sqrt(2), fullMat = TRUE, ...)

Arguments

• obj: object of class SpatialGrid or SpatialPixels
• maxdist: maximum distance to be considered (inclusive), expressed in number of grid cell (sqrt(2) results in queen neighbours)
• fullMat: use dist to compute distances from grid (row/col) indices; FALSE avoids forming the full distance matrix, at a large performance cost
• ...: arguments passed on to dist

Returns

Object of class nb, which is a list.

The nb object follows the convention of nb objects in package spdep; it is a list with each list element corresponding to a grid cell or pixel; the list element contains the indices of neighbours defined as cells less than maxdist away, measured in cell unit (N/S/E/W neighbour has distance 1).

Note

Unequal grid cell size is ignored; grid cell row/col indices are taken to be the coordinates from which distances are computed.

See Also

plot.nb in package spdep

Author(s)

Edzer Pebesma, edzer.pebesma@uni-muenster.de