is.valid: Check or fix polygon or extent validity

In terra: Spatial Data Analysis

Check or fix polygon or extent validity

Description

Check the validity of polygons or attempt to fix it. Or check the validity of a SpatExtent.

Usage

## S4 method for signature 'SpatVector'
is.valid(x, messages=FALSE, as.points=FALSE)

## S4 method for signature 'SpatVector'
makeValid(x, buffer=FALSE)

## S4 method for signature 'SpatExtent'
is.valid(x)

Arguments

x	SpatVector or SpatExtent
messages	logical. If TRUE the error messages are returned
as.points	logical. If TRUE, it is attempted to return locations where polygons are invalid as a SpatVector or points
buffer	logical. If TRUE the zero-width buffer method is used to create valid polygons. Be careful when using this method because it may result in data loss. For example, only a single part of a self-intersecting may be preserved. See the example below

Value

logical

See Also

topology

Examples

w <- vect("POLYGON ((0 -5, 10 0, 10 -10, 0 -5))")
is.valid(w)

w <- vect("POLYGON ((0 -5, 10 0, 10 -10, 4 -2, 0 -5))")
is.valid(w)
is.valid(w, TRUE)
v1 <- makeValid(w)
is.valid(v1)
v2 <- makeValid(w, buffer=TRUE)

plot(disagg(v1), col=c("light blue", "gray"))
# valid but incomplete
lines(v2, col="red", lwd=3)

plot(w)
points(cbind(4.54, -2.72), cex=2, col="red")

e <- ext(0, 1, 0, 1)
is.valid(e)

ee <- ext(0, 0, 0, 0)
is.valid(ee)

terra documentation built on Jan. 12, 2026, 9:07 a.m.