Draw simple-feature (sf) geometries

mark_sf() draws the geometry column of an sf object as a map layer: POINT/MULTIPOINT render as points, LINESTRING/MULTILINESTRING as polylines, and POLYGON/MULTIPOLYGON as filled paths (holes cut with the even-odd rule, so ring winding need not be canonical). Coordinates come from the geometry, so there are no x/y encodings; other aesthetics map feature attributes as usual, e.g. fill = AREA for a choropleth. Pair with coord_sf() to reproject and lock the map aspect ratio.

Usage

mark_sf(
  plot,
  ...,
  fill = NULL,
  color = NULL,
  alpha = NULL,
  linewidth = NULL,
  size = NULL,
  na_value = "grey80",
  blend = NULL,
  sketch = NULL,
  data = NULL
)

Arguments

plot

A PlotSpec (from vplot()).

...

Encodings mapping feature attributes to aesthetics: fill, color, alpha, linewidth, size. A geometry column is not encoded — it is read from the data.

fill, color, alpha, linewidth, size

Convenience aesthetic arguments; a constant or a mapped expression.

na_value

Fill colour for features whose mapped fill/color value is NA (drawn as a distinct legend swatch). Default "grey80".

blend

Optional blend mode (see mark_point()).

sketch

A sketch() spec giving the layer a hand-drawn look, or NULL (default) to inherit.

data

Optional layer data (an sf object); overrides the plot data.

Value

The modified PlotSpec.

Details

sf is an optional dependency (in Suggests); mark_sf() errors with an install hint if it is not available.

See also

coord_sf(), scale_fill_binned()

Examples

if (FALSE) { # \dontrun{
nc <- sf::st_read(system.file("shape/nc.shp", package = "sf"), quiet = TRUE)
vplot(nc) |> mark_sf(fill = BIR74) |> coord_sf()
} # }