sf (version 1.0-22)

st_line_project_point: Project point on linestring, interpolate along a linestring

Description

Project point on linestring, interpolate along a linestring

Usage

st_line_project(line, point, normalized = FALSE)
st_line_interpolate(line, dist, normalized = FALSE)

Value

st_line_project returns the distance(s) of point(s) along line(s), when projected on the line(s)

st_line_interpolate returns the point(s) at dist(s), when measured along (interpolated on) the line(s)

Arguments

line

object of class sfc with LINESTRING geometry

point

object of class sfc with POINT geometry

normalized

logical; if TRUE, use or return distance normalised to 0-1

dist

numeric or units, vector with distance value(s), in units of the coordinates

Details

arguments line, point and dist are recycled to common length when needed

Examples

st_line_project(st_as_sfc("LINESTRING (0 0, 10 10)"), st_as_sfc(c("POINT (0 0)", "POINT (5 5)")))
st_line_project(st_as_sfc("LINESTRING (0 0, 10 10)"), st_as_sfc("POINT (5 5)"), TRUE)
st_line_interpolate(st_as_sfc("LINESTRING (0 0, 1 1)"), 1)
st_line_interpolate(st_as_sfc("LINESTRING (0 0, 1 1)"), 1, TRUE)
# https://github.com/r-spatial/sf/issues/2542; use for geographic coordinates:
l1 <- st_as_sfc("LINESTRING (10.1 50.1, 10.2 50.2)", crs = 'OGC:CRS84')
dists = units::set_units(seq(0, sqrt(2)/10, length.out = 5), degrees)
st_line_interpolate(l1, dists)