gridindex2nb: create neighbourhood (nb) object from grid geometry

In sp: Classes and Methods for Spatial Data

create neighbourhood (nb) object from grid geometry

Description

create neighbourhood (nb) object from grid geometry

Usage

 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

Value

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.

Author(s)

Edzer Pebesma, [e-mail]

See Also

plot.nb in package spdep

sp documentation built on May 29, 2024, 5:33 a.m.