Simplify with Visvalingam-Whyatt

Reduces the number of points in each geometry by removing vertices whose effective area is below epsilon. Accepts linestrings, multilinestrings, polygons, and multipolygons.

Like ga_simplify_vw() but preserves topology by preventing self-intersections during simplification. Accepts linestrings, multilinestrings, polygons, and multipolygons.

Usage

ga_simplify_vw(geometry, epsilon)

ga_simplify_vw_preserve(geometry, epsilon)

Arguments

geometry

a GeoArrow linestring, multilinestring, polygon, or multipolygon array

epsilon

the simplification tolerance; length 1 or the same length as geometry

Value

a GeoArrow array of the same geometry type as the input

a GeoArrow array of the same geometry type as the input

References

SimplifyVw

SimplifyVwPreserve

See also

Other simplify: ga_simplify(), ga_simplify_idx()

Examples

fp <- system.file("shape/nc.shp", package = "sf")
nc <- as.data.frame(read_shapefile(fp))

# epsilon is an area here, not a distance as in ga_simplify()
head(as.vector(ga_n_coords(nc$geometry)), 3)
#> [1] 27 26 28
head(as.vector(ga_n_coords(ga_simplify_vw(nc$geometry, 0.001))), 3)
#> [1] 13 11 11