terra (version 1.9-46)

centroids: Centroids

Description

Get the centroids of polygons or lines, or centroid-like points that are guaranteed to be inside the polygons or on the lines.

Or get the (weighted) centroid of the cells with values (not NA) of a SpatRaster.

Usage

# S4 method for SpatVector
centroids(x, inside=FALSE, correct=FALSE)
# S4 method for SpatRaster
centroids(x, weighted=FALSE)

Value

SpatVector of points

Arguments

x

SpatVector

inside

logical. If TRUE the points returned are guaranteed to be inside the polygons or on the lines, but they are not the true centroids. True centroids may be outside a polygon, for example when a polygon is "bean shaped".

correct

If TRUE corrected centroids are returned for geometries in x that have a true centroid that is not inside the geometry. If inside=TRUE it is replaced with another point that is guaranteed to be inside the geometry. If it is FALSE, it is replaced with the nearest point on the border of the geometry

weighted

logical. If TRUE the centroids are computed as the weighted means of the coordinates of cells with values

Examples

f <- system.file("ex/lux.shp", package="terra")
v <- vect(f)
x <- centroids(v)
y <- centroids(v, TRUE)
z <- centroids(v, correct=TRUE) ## same as z in this case


f <- system.file("ex/elev.tif", package="terra")
r <- rast(f)
centroids(r)


p <- vect("POLYGON ((5.9 50, 6.3 50, 6.5 49.8, 6.3 49.6, 5.9 49.5, 6.3 49.7, 6.3 49.9, 5.9 50))")
plot(p)
points(centroids(p), col="red", cex=2)
points(centroids(p, inside=TRUE), col="blue", cex=2)
points(centroids(p, inside=FALSE, correct=TRUE), col="green", cex=2)