gridindex2nb.Rdcreate neighbourhood (nb) object from grid geometry
gridIndex2nb(obj, maxdist = sqrt(2), fullMat = TRUE, ...)
| 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 |
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).
Unequal grid cell size is ignored; grid cell row/col indices are taken to be the coordinates from which distances are computed.
plot.nb in package spdep