cartography (version 2.1.0)

getBorders: Extract Polygons Borders

Description

Extract borders between polygons.

Usage

getBorders(x, id, spdf, spdfid = NULL)

Arguments

x

an sf object, a simple feature collection or a SpatialPolygonsDataFrame.

id

identifier field in x or spdf, default to the first column. (optional)

spdf

deprecated, a SpatialPolygonsDataFrame. This SpatialPolygonsDataFrame has to be projected (planar coordinates).

spdfid

deprecated, identifier field in spdf, default to the first column of the spdf data frame. (optional)

Value

An sf object (MULTILINESTRING) of borders is returned. This object has three id fields: id, id1 and id2. id1 and id2 are ids of units that neighbour a border; id is the concatenation of id1 and id2 (with "_" as separator).

See Also

discLayer, getOuterBorders

Examples

# NOT RUN {
library(sp)
library(sf)
data(nuts2006)
# Get borders
nuts0.contig <- getBorders(x = nuts0.spdf)
# Plot Countries
plot(nuts0.spdf, border = NA, col = "grey60")
# Plot borders
plot(st_geometry(nuts0.contig), 
     col = sample(x = rainbow(nrow(nuts0.contig))), 
     lwd = 3, add = TRUE)

library(sf)
mtq <- st_read(system.file("shape/martinique.shp", package="cartography"))
# Get borders
mtq.borders <- getBorders(x = mtq)
# Plot polygons
plot(st_geometry(mtq), border = NA, col = "grey60")
# Plot borders
plot(st_geometry(mtq.borders), 
     col = sample(x = rainbow(nrow(nuts0.contig))), 
     lwd = 3, add = TRUE)
# }