Description Usage Arguments Value Author(s) Examples
Determines which polygons of a "SpatialPolygons"
object are at the border, i.e. have coordinates in common with the
spatial union of all polygons (constructed using
unionSpatialPolygons
).
1 2 | polyAtBorder(SpP, snap = sqrt(.Machine$double.eps),
method = "rgeos", ...)
|
SpP |
an object of class |
snap |
tolerance used to consider coordinates as identical. |
method |
method to use for |
... |
further arguments passed to the chosen |
logical vector of the same length as SpP
also inheriting its
row.names
.
Sebastian Meyer
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 | ## Load districts of Germany
load(system.file("shapes", "districtsD.RData", package = "surveillance"))
## Determine districts at the border and check the result on the map
if (requireNamespace("rgeos")) {
atBorder <- polyAtBorder(districtsD, method = "rgeos")
plot(districtsD, col = atBorder)
}
## For method = "polyclip", a higher snapping tolerance is required
## to obtain the correct result
if (requireNamespace("polyclip")) {
atBorder <- polyAtBorder(districtsD, snap = 1e-6, method = "polyclip")
plot(districtsD, col = atBorder)
}
|
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