topo-unary-gCoverageUnion: Coverage Union

Description Usage Arguments Author(s) See Also Examples

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

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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

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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 Dec. 15, 2021, 1:07 a.m.