sfc_polygon {sfheaders}

sfc POLYGON

Description

constructs an sfc of POLYGON objects

Usage

sfc_polygon(
  obj = NULL,
  x = NULL,
  y = NULL,
  z = NULL,
  m = NULL,
  polygon_id = NULL,
  linestring_id = NULL,
  close = TRUE
)

Arguments

obj

sorted matrix or data.frame

x

x geometry column

y

y geometry column

z

z geometry column

m

m geometry column

polygon_id

column of ids for polygons

linestring_id

column of ids for lines (within polygons)

close

logical indicating whether polygons should be closed. If TRUE, all polygons will be checked and force closed if possible

Value

sfc object of POLYGON geometries

notes

sfheaders functions do not perform any validity checks on the geometries. Nor do they set Coordinate Reference Systems, EPSG, PROJ4 or precision attributes.

The data.frame and matrices you send into the sfheader functions must be ordered.

Examples

m <- matrix(c(0,0,0,0,1,1), ncol = 2 )
sfc_polygon( m )

m <- matrix(c(0,0,0,0,0,1,0,1,1,1,2,2,1,2,3,1,3,2), ncol = 3, byrow = TRUE)
sfc_polygon( obj = m )
sfc_polygon( obj = m, polygon_id = 1 )
sfc_polygon( obj = m, linestring_id = 1 )

sfc_polygon( obj = m, linestring_id = 1, polygon_id = 1 )

sfc_polygon( obj = m, x = 2, y = 3 )
sfc_polygon( obj = m, x = 1, y = 2, z = 3 )
sfc_polygon( obj = m, x = 2, y = 3, linestring_id = 1, polygon_id = 1 )

df <- data.frame(
  ml_id = c(1,1,1,1,1,1,1,1,1,2,2,2,2,2,2)
  , l_id = c(1,1,1,2,2,2,3,3,3,1,1,1,2,2,2)
  , x = rnorm(15)
  , y = rnorm(15)
  , z = rnorm(15)
  , m = rnorm(15)
)

sfc_polygon( obj = df, x = "x", y = "y")
sfc_polygon( obj = df, x = "x", y = "y", z = "z")
sfc_polygon( obj = df, x = "x", y = "y", z = "z", m = "m")

sfc_polygon( obj = df, x = 2, y = 3)
sfc_polygon( obj = df, x = 2, y = 3, z = 4)
sfc_polygon( obj = df, x = 2, y = 3, z = 4, m = 5)

sfc_polygon( obj = df, polygon_id = "ml_id", linestring_id = "l_id" )
sfc_polygon( obj = df, polygon_id = 1, linestring_id = 2 )