`"SpatialPolygons"`

`poly2adjmat.Rd`

Wrapping around functionality of the spdep package, this function
computes the symmetric, binary (0/1), adjacency matrix from a
`"SpatialPolygons"`

object.
It essentially applies
```
nb2mat(poly2nb(SpP, ...), style="B",
zero.policy=zero.policy)
```

.

`poly2adjmat(SpP, ..., zero.policy = TRUE)`

- SpP
an object inheriting from

`"SpatialPolygons"`

.- ...
arguments passed to

`poly2nb`

. Its`snap`

argument might be particularly useful to handle maps with sliver polygons.- zero.policy
logical indicating if islands are allowed, see

`nb2mat`

.

a symmetric numeric indicator matrix of size `length(SpP)`

^2
representing polygon adjacencies.

(of this wrapper) Sebastian Meyer

`poly2nb`

in package spdep

```
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)
## the neighbourhood graph can be plotted with spdep
plot(spdep::mat2listw(adjmat), coordinates(fluBYBW@map))
}
```