如何在 R 中溶解折线

Question

I have a large polyline shapefile that needs to be dissolved. However, the examples online only relate to polygons not polylines for example gUnaryUnion . I am reading in my shapefile using st_read from the sf package. Any help would be appreciated.

Answer 1

If I understand your question, one option is to use dplyr .

library(sf)
library(dplyr)

# get polyline road data
temp_shapefile <- tempfile()
download.file("https://www2.census.gov/geo/tiger/TIGER2017//ROADS/tl_2017_06075_roads.zip", temp_shapefile)
temp_dir <- tempdir()
unzip(temp_shapefile, exdir = temp_dir)

sf_roads <- read_sf(file.path(temp_dir,'tl_2017_06075_roads.shp'))

Use the RTTYP field to reduce the polyline from ~4000 unique segments to 6 segments.

sf_roads_summarized <- sf_roads %>%
  group_by(RTTYP) %>%
  summarize()

Answer 2

I manged to achieve this by using st_combine .