st_nearest_feature {sf}

get index of nearest feature

Description

get index of nearest feature

Usage

st_nearest_feature(
  x,
  y,
  ...,
  check_crs = TRUE,
  longlat = isTRUE(st_is_longlat(x))
)

Arguments

x

object of class sfg, sfc or sf

y

object of class sfg, sfc or sf; if missing, features in x will be compared to all remaining features in x.

...

ignored

check_crs

logical; should x and y be checked for CRS equality?

longlat

logical; does x have ellipsoidal coordinates?

Value

for each feature (geometry) in x the index of the nearest feature (geometry) in set y, or in the remaining set of x if y is missing; empty geometries result in NA indexes

See Also

st_nearest_points for finding the nearest points for pairs of feature geometries

Examples

ls1 = st_linestring(rbind(c(0,0), c(1,0)))
ls2 = st_linestring(rbind(c(0,0.1), c(1,0.1)))
ls3 = st_linestring(rbind(c(0,1), c(1,1)))
(l = st_sfc(ls1, ls2, ls3))

p1 = st_point(c(0.1, -0.1))
p2 = st_point(c(0.1, 0.11))
p3 = st_point(c(0.1, 0.09))
p4 = st_point(c(0.1, 0.9))

(p = st_sfc(p1, p2, p3, p4))
try(st_nearest_feature(p, l))
try(st_nearest_points(p, l[st_nearest_feature(p,l)], pairwise = TRUE))

r = sqrt(2)/10
b1 = st_buffer(st_point(c(.1,.1)), r)
b2 = st_buffer(st_point(c(.9,.9)), r)
b3 = st_buffer(st_point(c(.9,.1)), r)
circles = st_sfc(b1, b2, b3)
plot(circles, col = NA, border = 2:4)
pts = st_sfc(st_point(c(.3,.1)), st_point(c(.6,.2)), st_point(c(.6,.6)), st_point(c(.4,.8)))
plot(pts, add = TRUE, col = 1)
# draw points to nearest circle:
nearest = try(st_nearest_feature(pts, circles))
if (inherits(nearest, "try-error")) # GEOS 3.6.1 not available
  nearest = c(1, 3, 2, 2)
ls = st_nearest_points(pts, circles[nearest], pairwise = TRUE)
plot(ls, col = 5:8, add = TRUE)
# compute distance between pairs of nearest features:
st_distance(pts, circles[nearest], by_element = TRUE)