wk_vertices: Extract vertices

In wk: Lightweight Well-Known Geometry Parsing

Extract vertices

Description

These functions provide ways to extract individual coordinate values. Whereas wk_vertices() returns a vector of coordinates as in the same format as the input, wk_coords() returns a data frame with coordinates as columns.

Usage

wk_vertices(handleable, ...)

wk_coords(handleable, ...)

wk_coords(handleable, use_z = NA, use_m = NA) <- value

wk_vertex_filter(handler, add_details = FALSE)

Arguments

handleable	A geometry vector (e.g., wkb(), wkt(), xy(), rct(), or sf::st_sfc()) for which wk_handle() is defined.
...	Passed to the wk_handle() method.
use_z, use_m	Used to declare the output type. Use TRUE to ensure the output has that dimension, FALSE to ensure it does not, and NA to leave the dimension unchanged.
value	An xy(), xyz(), xym(), or xyzm() of coordinates used to replace values in the input. Use NA to keep the existing value.
handler	A wk_handler object.
add_details	Use TRUE to add a "wk_details" attribute, which contains columns feature_id, part_id, and ring_id.

Details

⁠wk_coords<-⁠ is the replacement-function version of 'wk_coords'. Using the engine of wk_trans_explicit() the coordinates of an object can be transformed in a generic way using R functions as needed.

Value

• wk_vertices() extracts vertices and returns the in the same format as the handler

• wk_coords() returns a data frame with columns columns feature_id (the index of the feature from whence it came), part_id (an arbitrary integer identifying the point, line, or polygon from whence it came), ring_id (an arbitrary integer identifying individual rings within polygons), and one column per coordinate (x, y, and/or z and/or m).

Examples

wk_vertices(wkt("LINESTRING (0 0, 1 1)"))
wk_coords(wkt("LINESTRING (0 0, 1 1)"))

# wk_coords() replacement function
x <- xy(1:5, 1:5)
y <- as_wkt(x)
wk_coords(y) <- cbind(5:1, 0:4)
wk_coords(x) <- y[5:1]
y
x

wk documentation built on Oct. 12, 2024, 1:07 a.m.