UK Countries: create simplified boundaries with buffers

Load packages, read data, and source custom scripts

rm(list = ls())
library(sf)

#> Linking to GEOS 3.7.1, GDAL 2.4.0, PROJ 5.2.0

library(ggplot2)
library(units)

#> udunits system database from /usr/share/xml/udunits

path_proj <- day2day::git_path()
path_data <- file.path(path_proj, "data")
path_raw <- file.path(path_data, "raw")
path_cleaned <- file.path(path_data, "cleaned")
path_src <- file.path(path_proj, "src")
path_sf <- file.path(path_src, "sfaux")

devtools::load_all(path_sf)

#> Loading sfaux

path_uk <- file.path(path_raw, "boundaries",
                      "Countries_December_2017_Full_Clipped_Boundaries_UK_WGS84.shp")
uk <- st_read(path_uk)

#> Reading layer `Countries_December_2017_Full_Clipped_Boundaries_UK_WGS84' from data source `/home/rstudio/Documents/Projects/land-suitability/data/raw/boundaries/Countries_December_2017_Full_Clipped_Boundaries_UK_WGS84.shp' using driver `ESRI Shapefile'
#> Simple feature collection with 4 features and 10 fields
#> geometry type:  MULTIPOLYGON
#> dimension:      XY
#> bbox:           xmin: -8.650007 ymin: 49.86468 xmax: 1.763546 ymax: 60.86077
#> CRS:            4326

uk_27700 <- st_transform(uk, crs = 27700)

Simplified (buffered) UK boundaries per country

buffer_dist <- set_units(5, "km")
uk_simple <- st_simplify(uk_27700, dTolerance = 500)
uk_buffer <- st_buffer(uk_simple, buffer_dist)

lwd <- 0.3
ggplot(uk_buffer) +
    geom_sf(aes(col = "buffered"), fill = NA, size = lwd) +
    geom_sf(aes(col = "simplified"), data = uk_simple, fill = NA, size = lwd) +
    coord_sf(datum = 27700) +
    labs(colour = "UK") +
    theme_void()

Simplified and unified (buffered) UK boundaries

uk_union <- st_union(st_geometry(uk_simple))
uk_union <- st_union_unique(uk_union)
uk_union_buffer <- st_buffer(uk_union, set_units(5, "km"))

ggplot(uk_union_buffer) +
    geom_sf(aes(col = "buffered"), fill = NA, size = lwd) +
    geom_sf(aes(col = "simplified"), uk_union, fill = NA, size = lwd) +
    coord_sf(datum = 27700) +
    labs(colour = "UK union") +
    theme_void()

A (buffered) UK bounding box

bbox <- st_as_sfc(st_bbox(uk_27700))
bbox_buffer <- st_as_sfc(st_bbox(uk_buffer))

ggplot(bbox_buffer) +
    geom_sf(aes(col = "buffered"), fill = NA, size = lwd) +
    geom_sf(aes(col = "original"), bbox, fill = NA, size = lwd) +
    geom_sf(data = uk_union_buffer, col = "gray", size = lwd) +
    coord_sf(datum = 27700) +
    labs(colour = "Bounding box") +
    theme_void()

Save new UK files

uk_simple_file <- file.path(path_cleaned, "uk_simple.gpkg")

st_write(uk_simple,       uk_simple_file, delete_dsn = TRUE, layer = "simple")

#> Deleting source `/home/rstudio/Documents/Projects/land-suitability/data/cleaned/uk_simple.gpkg' using driver `GPKG'
#> Writing layer `simple' to data source `/home/rstudio/Documents/Projects/land-suitability/data/cleaned/uk_simple.gpkg' using driver `GPKG'
#> Writing 4 features with 10 fields and geometry type Multi Polygon.

st_write(uk_buffer,       uk_simple_file, delete_layer = TRUE, layer = "simple_buffer")

#> Deleting layer `simple_buffer' failed
#> Writing layer `simple_buffer' to data source `/home/rstudio/Documents/Projects/land-suitability/data/cleaned/uk_simple.gpkg' using driver `GPKG'
#> Writing 4 features with 10 fields and geometry type Unknown (any).

st_write(uk_union,        uk_simple_file, delete_layer = TRUE, layer = "union")

#> Deleting layer `union' failed
#> Writing layer `union' to data source `/home/rstudio/Documents/Projects/land-suitability/data/cleaned/uk_simple.gpkg' using driver `GPKG'
#> Writing 1 features with 0 fields and geometry type Multi Polygon.

st_write(uk_union_buffer, uk_simple_file, delete_layer = TRUE, layer = "union_buffer")

#> Deleting layer `union_buffer' failed
#> Writing layer `union_buffer' to data source `/home/rstudio/Documents/Projects/land-suitability/data/cleaned/uk_simple.gpkg' using driver `GPKG'
#> Writing 1 features with 0 fields and geometry type Multi Polygon.

st_write(bbox,            uk_simple_file, delete_layer = TRUE, layer = "bbox")

#> Deleting layer `bbox' failed
#> Writing layer `bbox' to data source `/home/rstudio/Documents/Projects/land-suitability/data/cleaned/uk_simple.gpkg' using driver `GPKG'
#> Writing 1 features with 0 fields and geometry type Polygon.

st_write(bbox_buffer,     uk_simple_file, delete_layer = TRUE, layer = "bbox_buffer")

#> Deleting layer `bbox_buffer' failed
#> Writing layer `bbox_buffer' to data source `/home/rstudio/Documents/Projects/land-suitability/data/cleaned/uk_simple.gpkg' using driver `GPKG'
#> Writing 1 features with 0 fields and geometry type Polygon.

Time to execute the task

Only useful when executed with Rscript.

proc.time()

#>    user  system elapsed 
#>  36.565   1.483  38.191