topo-unary-gCoverageUnion: Coverage Union

In rgeos: Interface to Geometry Engine - Open Source ('GEOS')

Coverage Union

Description

GEOSCoverageUnion is an optimized union algorithm for polygonal inputs that are correctly noded and do not overlap. It will not generate an error (return NULL) for inputs that do not satisfy this constraint.

Usage

gCoverageUnion(spgeom, byid=FALSE, id = NULL)

Arguments

spgeom	sp object as defined in package sp
byid	Logical determining if the function should be applied across subgeometries (TRUE) or the entire object (FALSE)
id	Character vector defining id labels for the resulting geometries, if unspecified returned geometries will be labeled based on their parent geometries' labels.

Author(s)

Roger Bivand

See Also

gUnaryUnion

Examples

run <- FALSE
if (require(maptools)) run <- TRUE
if (run) {
    nc1 <- readShapePoly(system.file("shapes/sids.shp", package="maptools")[1],
        proj4string=CRS("+proj=longlat +datum=NAD27"))
}
if (run) {
    print(system.time(oU <- gUnionCascaded(nc1)))
    if (version_GEOS0() >= "3.8.0") {
        print(system.time(oCU <- gCoverageUnion(nc1)))
    }
}

rgeos documentation built on July 26, 2023, 5:42 p.m.