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Combine geometries

Source: R/combine.R, R/extendr-wrappers.R
combine_geoms.Rd

Given a vector of geometries combine them into a single geometry.

Usage

combine_geoms(x)

union_geoms(x)

Arguments

x

an object of class rsgeo

Value

An object of class rsgeo of length one.

Details

combine_geoms()

combine_geoms() combines a vector of geometries into a vector of length one their MULTI counterpart.

  • rs_POINT and rs_MULTIPOINT -> rs_MULTIPOINT

  • rs_LINESTRING and rs_MULTILINESTRING -> rs_MULTILINESTRING

  • rs_POLYGON and rs_MULTIPOLYGON -> rs_MULTIPOLYGON

  • rs_GEOMETRYCOLLECTION is not supported

union_geoms()

union_geoms() creates a union of all geometries removing repeated points or dissolving shared boundaries.

  • rs_POINT - combines and removes repeated points

  • rs_MULTIPOINT - combines removes repeated points

  • rs_LINESTRING - combines and removes duplicated points

  • rs_MULTILINESTRING - combines and removes duplicated points

  • rs_POLYGON - unions geometries into a single geometry

  • rs_MULTIPOLYGON - unions geometries into a single geometry

Examples

pnts <- geom_point(runif(10), runif(10))
combine_geoms(pnts)
#> <rs_POINT[1]>
#> [1] MultiPoint([Point(Coord { x: 0.4734771477524191, y: 0.9752697139047086 }),...

lns <- geom_linestring(1:100, runif(100, -10, 10), rep.int(1:5, 20))
union_geoms(lns)
#> <rs_MULTILINESTRING[1]>
#> [1] MultiLineString([LineString([Coord { x: 1.0, y: -3.2701129419729114 }, Coo...

x <- c(0, 1, 1, 0, 0)
y <- c(0, 0, 1, 1, 0)

p1 <- geom_polygon(x, y)
p2 <- geom_polygon(x - 1, y + 0.5)

z <- c(p1, p2)

res <- union_geoms(z)
res
#> <rs_MULTIPOLYGON[1]>
#> [1] MultiPolygon([Polygon { exterior: LineString([Coord { x: 0.0, y: 0.5 }, Co...

if (rlang::is_installed(c("sf", "wk"))) {
  plot(z)
  plot(res, lty = 3, border = "blue", add = TRUE, lwd = 4)
}