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Day 7 of 30 Day Card Challenge: « Accessibility » (earlier).
Well, let’s be rebellious and seek inaccessibility instead; more precisely the pole of inaccessibility of France (de Hexagon): the furthest location from the border. Not to be confused with the center of gravity.
library(sf) library(dplyr) library(ggplot2) library(glue) library(purrr) library(polylabelr)
Facts
We will again use the French administrative units (get the facts from here after).
# France boundary
fr <- read_sf("~/data/adminexpress/adminexpress_cog_simpl_000_2022.gpkg",
layer = "region") |>
filter(insee_reg > "06",
insee_reg != "94") |>
st_transform("EPSG:2154") |>
st_union()
# French communes to get the point name
com <- read_sf("~/data/adminexpress/adminexpress_cog_simpl_000_2022.gpkg",
layer = "commune") |>
filter(insee_reg > "06",
insee_reg != "94") |>
st_transform("EPSG:2154")Calculate the POI
Determine the inaccessibility pole of France with {polylabelr} and intersect it with the local authority low to find the nearest city.
fr_poi <- poi(fr) |>
pluck(1) |>
as_tibble() |>
st_as_sf(coords = c("x", "y"), crs = "EPSG:2154") |>
st_join(com)
fr_poi_circle <- fr_poi |>
mutate(geometry = st_buffer(geometry, dist))
fr_centroid <- fr |>
st_centroid()It appears to be inside Saint-Palais in the Cher department.
Card
fr_poi |>
ggplot() +
geom_sf(data = fr) +
geom_sf(data = fr_poi_circle, linewidth = 1, linetype = 3) +
geom_sf(data = fr_centroid, color = "darkgrey") +
geom_sf() +
geom_sf_text(aes(label = nom), vjust = -.5) +
labs(title = "Pole of inaccessibility",
subtitle = "France",
x = "", y = "",
caption = glue("https://r.iresmi.net/ - {Sys.Date()}
data from IGN Adminexpress 2022")) +
theme_minimal() +
theme(plot.caption = element_text(size = 6,
color = "darkgrey"))
Figure 1: Inaccessibility pole of France (black). The gray dot is the center of gravity
Related
#Inaccessibility #bloggers