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Reverse a cycle's winding direction

Source: R/merge_coincident.R
reverse_cycle.Rd

Reverse a cycle's winding direction

Usage

reverse_cycle(cycle)

Arguments

cycle

Integer vector of .vx IDs forming a closed cycle

Value

The same vertices in reversed order (opposite winding)

Details

Flips the traversal direction of a cycle without changing coordinates. Useful for converting between winding conventions.

Examples

x <- wk::as_wkb("POLYGON ((0 0, 1 0, 1 1, 0 1, 0 0))")
pool <- establish_topology(x)
merged <- merge_coincident(pool)
cycles <- find_cycles(merged)
reverse_cycle(cycles[[1]])
#> [1] 4 3 2 1