Make a map of Montpellier with R and openstreetmap data

montpellier_OSM_city_map.R

# code from https://gist.github.com/d-qn/4f1c4ed80a4fd6a76cd1153c89f56134

library(tidyverse)
library(sf)
library(osmdata) # to get openstreetmap geo data

# settings
# olivier: get data on Montpellier
bb <- getbb('Montpellier, France') # define the bbox, will be used to fetch OSM data within that box
dest_proj <- 2056

# OSM overpass query
q <- opq(bbox = bb)

## Get OSM geo data, reproject and discard unused features
q_bg <- q %>% 
  add_osm_feature(key = 'building') %>% 
  osmdata_sf() 

# bind polygons and multipolygons buildings into one data.frame
buildings <- q_bg$osm_polygons %>% 
  st_transform(dest_proj) %>% 
  select(name, osm_id, building) 

buildings <- bind_rows(
  buildings,
  q_bg$osm_multipolygons %>% 
    st_transform(dest_proj) %>% 
    select(name, osm_id, building)
) %>% 
  st_make_valid()

# all roads  
q_rd <- q %>% 
  add_osm_feature(key = 'highway') %>% 
  osmdata_sf() 

# recode roads type to numeric
roads <- q_rd$osm_lines %>% 
  st_transform(dest_proj) %>% 
  select(name, osm_id, highway) %>% 
  mutate(type = case_when(
    highway %in% c("motorway", "motorway_link") ~ 1,
    highway %in% c("primary", "primary_link") ~ 2,
    highway %in% c("secondary", "secondary_link") ~ 3,    
    highway %in% c("tertiary", "tertiary_link") ~ 4,   
    T ~ 5
  ))

# all railway s
q_ry <- q %>% 
  add_osm_feature(key = 'railway')  %>% 
  osmdata_sf()

railways <- q_ry$osm_lines %>% 
  st_transform(dest_proj) %>% 
  select(railway) %>% 
  mutate(type = case_when(
    railway %in% c("rail", "light_rail") ~ 1,
    railway %in% c("subway") ~ 2,
    T ~ 3
  ))

ggplot() +
  geom_sf(data = buildings, 
          fill = "#ECD89DFF",
          size = 0, alpha = 0.25) +
  geom_sf(data = roads, 
          aes(colour = type, size =1/type),
          colour = "white") + 
# olivier: remove railways
#  geom_sf(data = railways, size = 0.2, 
#          colour = "#EEBCB1FF" )+
  scale_size(range =  c(0.03, 0.2)) +
  scale_alpha(range =  c(0.8, 0.98)) +
  theme_void() +
  theme(plot.background = element_rect(fill = "#293133", "293133"),
        legend.position = "none") 

# save
# olivier: add resolution dpi = 600
ggsave("montpeul.png", dpi = 600)