Geometry constructors

These functions provide a means to construct geometries from data frames, possibly using dplyr::group_by() and dplyr::summarise(). Collections contain zero or more objects of type geo_point(), geo_linestring(), geo_polygon(), geo_multipoint(), geo_multilinestring(), and/or geo_multipolygon(). See wkutils::coords_point_translate_wkb() and related functions for high-performance methods to create these vectors.

geo_collection(feature = wksxp(), srid = NA)

geo_point(xy = geo_xy(), srid = NA)

geo_linestring(xy = geo_xy(), srid = NA)

geo_polygon(xy = geo_xy(), ring = 1L, srid = NA)

geo_multipoint(feature = wksxp(), srid = NA)

geo_multilinestring(feature = wksxp(), srid = NA)

geo_multipolygon(feature = wksxp(), srid = NA)

Arguments

feature	A vector of one or more features. For multi geometries, this must be a collection that only contains that type (e.g., multipolygons can only be composed of polygons).
srid	A spatial reference identifier, coerced to an integer by as_geo_srid(). These identifiers can and should be managed outside of geovctrs except for 0, which is interpreted as "not set".
xy	A geo_xy() of coordinates
ring	A vector whose unique values separate rings. Row order matters: the first value encountered will identify the outer ring.

Value

A wk::wksxp() of length 1.

Examples

# geo_point() and family all return a wk::wksxp() of length 1
c(geo_point(geo_xy(0, 1)), geo_point(geo_xy(1, 2)))
#> <wk_wksxp[2]>
#> [1] <POINT (0 1)> <POINT (1 2)>

# linestring
geo_linestring(geo_xy(1:5, 2:6))
#> <wk_wksxp[1]>
#> [1] <LINESTRING (1 2, 2 3, 3 4...>

# a polygon
geo_polygon(geo_xy(c(0, 10, 0, 0), c(0, 0, 10, 0)))
#> <wk_wksxp[1]>
#> [1] <POLYGON ((0 0, 10 0, 0 10...>

# polygon with a hole
poly_hole <- geo_polygon(
  geo_xy(
    c(35, 45, 15, 10, 35, 20, 35, 30, 20),
    c(10, 45, 40, 20, 10, 30, 35, 20, 30)
  ),
  ring = c(1, 1, 1, 1, 1, 2, 2, 2, 2)
)

# multipoint
geo_multipoint(
  c(geo_point(geo_xy(10, 30)), geo_point(geo_xy(12, 11)))
)
#> <wk_wksxp[1]>
#> [1] <MULTIPOINT ((10 30), (12 11))>

# multilinestring
geo_multilinestring(
  c(
    geo_linestring(geo_xy(0:1, 0:1)),
    geo_linestring(geo_xy(c(12, 30), c(11, 10)))
  )
)
#> <wk_wksxp[1]>
#> [1] <MULTILINESTRING ((0 0, 1 1), (12 11...>

# multipolygon
geo_multipolygon(
  geo_polygon(geo_xy(c(0, 10, 0, 0), c(0, 0, 10, 0)))
)
#> <wk_wksxp[1]>
#> [1] <MULTIPOLYGON (((0 0, 10 0, 0 10...>

# nested geo_collection()
c(geo_point(geo_xy(0, 1)), geo_collection(geo_point(geo_xy(1, 2))))
#> <wk_wksxp[2]>
#> [1] <POINT (0 1)>                      <GEOMETRYCOLLECTION (POINT (1 2))>