if (requireNamespace("spdep")) {
## generate adjacency matrix for districts of Bayern and Baden-Wuerttemberg
data("fluBYBW")
adjmat <- poly2adjmat(fluBYBW@map)
## same as already stored in the neighbourhood slot (in different order)
stopifnot(all.equal(adjmat,
neighbourhood(fluBYBW)[rownames(adjmat),colnames(adjmat)]))
## a visual check of the district-specific number of neighbours
plot(fluBYBW@map)
text(coordinates(fluBYBW@map), labels=rowSums(adjmat==1), font=2, col=2)
}
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