snapTo: Snap points to the edge of lines or polygons

In terra: Spatial Data Analysis

Snap points to the edge of lines or polygons

Description

Move the points in x onto the edge of the corresponding line or polygon in y. A point that touches the the target geometry is not changed. A point that is outside the geometry is moved to the nearest location on the edge (the boundary of a polygon, or the line itself).

Usage

## S4 method for signature 'SpatVector,SpatVector'
snapTo(x, y, paired=TRUE, ...)

Arguments

x	SpatVector of points
y	SpatVector of lines or polygons. Either with the same number of geometries as there are points in x, or with a single geometry
paired	logical. If TRUE the points in x are paired with the geometries in y (point i with geometry i). y may instead have a single geometry, in which case all points are snapped to that geometry. Otherwise the points in x are snapped to any geometry in y
...	additional arguments. None implemented

Value

SpatVector of points

See Also

nearest, distance, furdist

Examples

crs <- "+proj=utm +zone=1"
p <- vect("POLYGON ((0 0, 8 0, 8 9, 0 9, 0 0))", crs=crs)

# one point inside the polygon (unchanged), one outside (snapped to the edge)
pts <- vect(cbind(c(4, 12), c(4, 4)), crs=crs)
s <- snapTo(pts, p)
crds(s)

# snap to a line
L <- vect("LINESTRING (0 0, 10 0)", crs=crs)
q <- vect(cbind(c(5, 5), c(0, 3)), crs=crs)
crds(snapTo(q, L))

terra documentation built on Aug. 22, 2026, 5:07 p.m.