st_nearest_feature: get index of nearest feature

In sf: Simple Features for R

Description

get index of nearest feature

Usage

st_nearest_feature(x, y)

Arguments

x	object of class sfg, sfc or sf
y	object of class sfg, sfc or sf

Value

for each feature (geometry) in x the index of the nearest feature (geometry) in set y; 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)

Example output

Linking to GEOS 3.8.0, GDAL 3.0.4, PROJ 6.3.1
Geometry set for 3 features 
geometry type:  LINESTRING
dimension:      XY
bbox:           xmin: 0 ymin: 0 xmax: 1 ymax: 1
CRS:            NA
LINESTRING (0 0, 1 0)
LINESTRING (0 0.1, 1 0.1)
LINESTRING (0 1, 1 1)
Geometry set for 4 features 
geometry type:  POINT
dimension:      XY
bbox:           xmin: 0.1 ymin: -0.1 xmax: 0.1 ymax: 0.9
CRS:            NA
POINT (0.1 -0.1)
POINT (0.1 0.11)
POINT (0.1 0.09)
POINT (0.1 0.9)
[1] 1 2 2 3
Geometry set for 4 features 
geometry type:  LINESTRING
dimension:      XY
bbox:           xmin: 0.1 ymin: -0.1 xmax: 0.1 ymax: 1
CRS:            NA
LINESTRING (0.1 -0.1, 0.1 0)
LINESTRING (0.1 0.11, 0.1 0.1)
LINESTRING (0.1 0.09, 0.1 0.1)
LINESTRING (0.1 0.9, 0.1 1)

sf documentation built on March 17, 2021, 5:08 p.m.