st_segments: Split polygons or lines to segments

View source: R/st_segments.R

st_segmentsR Documentation

Split polygons or lines to segments

Description

Split lines or polygons to separate segments.

Usage

st_segments(x, progress = TRUE)

Arguments

x

An object of class sfg, sfc or sf, with geometry type LINESTRING, MULTILINESTRING, POLYGON or MULTIPOLYGON

progress

Display progress bar? (default TRUE)

Value

An sf layer of type LINESTRING where each segment is represented by a separate feature

Examples

# Sample geometries
s1 = rbind(c(0,3),c(0,4),c(1,5),c(2,5))
ls = st_linestring(s1)
s2 = rbind(c(0.2,3), c(0.2,4), c(1,4.8), c(2,4.8))
s3 = rbind(c(0,4.4), c(0.6,5))
mls = st_multilinestring(list(s1,s2,s3))
p1 = rbind(c(0,0), c(1,0), c(3,2), c(2,4), c(1,4), c(0,0))
p2 = rbind(c(1,1), c(1,2), c(2,2), c(1,1))
pol = st_polygon(list(p1,p2))
p3 = rbind(c(3,0), c(4,0), c(4,1), c(3,1), c(3,0))
p4 = rbind(c(3.3,0.3), c(3.8,0.3), c(3.8,0.8), c(3.3,0.8), c(3.3,0.3))[5:1,]
p5 = rbind(c(3,3), c(4,2), c(4,3), c(3,3))
mpol = st_multipolygon(list(list(p1,p2), list(p3,p4), list(p5)))

# Geometries ('sfg')
opar = par(mfrow = c(1, 2))

plot(ls)
seg = st_segments(ls, progress = FALSE)
plot(seg, col = rainbow(length(seg)))
text(st_coordinates(st_centroid(seg)), as.character(1:length(seg)))

plot(mls)
seg = st_segments(mls, progress = FALSE)
plot(seg, col = rainbow(length(seg)))
text(st_coordinates(st_centroid(seg)), as.character(1:length(seg)))

plot(pol)
seg = st_segments(pol, progress = FALSE)
plot(seg, col = rainbow(length(seg)))
text(st_coordinates(st_centroid(seg)), as.character(1:length(seg)))

plot(mpol)
seg = st_segments(mpol, progress = FALSE)
plot(seg, col = rainbow(length(seg)))
text(st_coordinates(st_centroid(seg)), as.character(1:length(seg)))

par(opar)

# Columns ('sfc')
opar = par(mfrow = c(1, 2))

ls = st_sfc(ls)
plot(ls)
seg = st_segments(ls, progress = FALSE)
plot(seg, col = rainbow(length(seg)))
text(st_coordinates(st_centroid(seg)), as.character(1:length(seg)))

ls2 = st_sfc(c(ls, ls + c(1, -1), ls + c(-3, -1)))
plot(ls2)
seg = st_segments(ls2, progress = FALSE)
plot(seg, col = rainbow(length(seg)))
text(st_coordinates(st_centroid(seg)), as.character(1:length(seg)))

mls = st_sfc(mls)
plot(mls)
seg = st_segments(mls, progress = FALSE)
plot(seg, col = rainbow(length(seg)))
text(st_coordinates(st_centroid(seg)), as.character(1:length(seg)))

mls2 = st_sfc(c(mls, mls + c(1, -2)))
plot(mls2)
seg = st_segments(mls2, progress = FALSE)
plot(seg, col = rainbow(length(seg)))
text(st_coordinates(st_centroid(seg)), as.character(1:length(seg)))

pol = st_sfc(pol)
plot(pol)
seg = st_segments(pol, progress = FALSE)
plot(seg, col = rainbow(length(seg)))
text(st_coordinates(st_centroid(seg)), as.character(1:length(seg)))

mpol = st_sfc(mpol)
plot(mpol)
seg = st_segments(mpol, progress = FALSE)
plot(seg, col = rainbow(length(seg)))
text(st_coordinates(st_centroid(seg)), as.character(1:length(seg)))

mpol2 = st_sfc(c(mpol, mpol + c(5, 2)))
plot(mpol2)
seg = st_segments(mpol2, progress = FALSE)
plot(seg, col = rainbow(length(seg)))
text(st_coordinates(st_centroid(seg)), as.character(1:length(seg)))

par(opar)

# Layers ('sf')
opar = par(mfrow = c(1, 2))

mpol_sf = st_sf(id = 1:2, type = c("a", "b"), geom = st_sfc(c(mpol, mpol + c(5, 2))))
plot(st_geometry(mpol_sf))
seg = st_segments(mpol_sf, progress = FALSE)
plot(st_geometry(seg), col = rainbow(nrow(seg)))
text(st_coordinates(st_centroid(seg)), as.character(1:nrow(seg)))

par(opar)


michaeldorman/nngeo documentation built on June 4, 2022, 12:49 a.m.