#30DayMapChallenge 2021 - Day 05 - OSM

hamilton_street_colours.R

# Create a map of streets in Hamilton, New Zealand
# coloured by the type of street name.
# For #30DayMapChallenge 2021 - Day 05 - OpenStreetMap
# (Whilst I'm not getting the data from OSM, the LINZ
#  data is loaded into OSM because of its open licence,
#  and I've used OSM data for other maps :-)
#   -- David Friggens, 2 December 2021

library(dplyr)
library(stringr)
library(sf)
library(ggplot2)
library(Manu)
library(ggtext)
library(glue)

FONT <- "Rye"

# Read data --------------------------------------------------------------

# From https://data.linz.govt.nz/layer/53382-nz-roads-addressing/
roads <- 
  read_sf("roads/nz-roads-addressing.gpkg")

roads <- 
  roads %>% 
  mutate(
    road_name_type =
      case_when(
        !is.na(road_name_type) ~ road_name_type,
        full_road_name %>% str_detect("^State Highway") ~ "Highway",
        full_road_name %>% str_detect("^Ara[ -]|^Te Ara ") ~ "Ara",
        full_road_name %>% str_detect("^Rue ") ~ "Rue",
        full_road_name %>% str_detect("^Access Road|^Main Road") ~ "Road",
        TRUE ~ full_road_name %>% str_replace(" East$| West$| North$| South$| [0-9]+$", "") %>% str_extract("[^ ]+$")
      )
  )

# From https://datafinder.stats.govt.nz
urban_areas <- 
  read_sf("statsnz/urban-rural-2021-clipped-generalised.gpkg") %>% 
  select(area_code = UR2021_V1_00,
         area_name = UR2021_V1_00_NAME,
         urban_type = IUR2021_V1_00_NAME) %>% 
  filter(urban_type %>% str_detect("rban"))

roads <- 
  roads %>% 
  st_transform(crs = st_crs(urban_areas))


# Hamilton ----------------------------------------------------------------

hamilton <- 
  urban_areas %>% 
  filter(area_name == "Hamilton")
hamilton_roads <- 
  hamilton %>% 
  st_intersection(roads)

hamilton_top_types <- 
  hamilton_roads %>%
  st_drop_geometry() %>% 
  filter(!is.na(road_name_type)) %>% 
  count(road_name_type) %>%
  arrange(desc(n)) %>% 
  head(6) %>% 
  pull(road_name_type)

hamilton_roads <- 
  hamilton_roads %>% 
  mutate(road_name_type = if_else(is.na(road_name_type) |
                                    ! road_name_type %in% hamilton_top_types,
                                  "Other",
                                  road_name_type))

PALETTE <- get_pal("Pohutukawa")
COL_BG <- "grey80"

hamilton_title <- 
  tibble(x = 1806465, y = 5825200,
         label = "The Streets of Hamilton, NZ")
hamilton_legend <- 
  tibble(x = 1806465, y = 5824000, 
         label = glue("Where would you find<br>",
                      "a <span style='color:{PALETTE[1]};'>{hamilton_top_types[1]}</span>,<br>",
                      "<span style='color:{PALETTE[2]};'>{hamilton_top_types[2]}</span>,<br>",
                      "<span style='color:{PALETTE[3]};'>{hamilton_top_types[3]}</span>,<br>",
                      "<span style='color:{PALETTE[4]};'>{hamilton_top_types[4]}</span>,<br>",
                      "<span style='color:{PALETTE[5]};'>{hamilton_top_types[5]}</span>,<br>",
                      "or a <span style='color:{PALETTE[6]};'>{hamilton_top_types[6]}</span>?",
         ))
hamilton_data_note <- 
  tibble(x = 1792600, y = 5808800,
         label = "#30DayMapChallenge 2021 - Day 05 - OpenStreetMap<br>Data from Land Information NZ<br>(which can also be sourced from OSM)")
hamilton_credit <- 
  tibble(x = 1806465, y = 5808800,
         label = "David Friggens @dakvid")

gg_hamilton <- 
  ggplot() +
  geom_sf(data = hamilton,
          fill = "white",
          colour = "black", size = 2) +
  geom_sf(data = hamilton_roads %>% filter(road_name_type == "Other"),
          size = 0.8,
          colour = COL_BG) +
  geom_sf(data = hamilton_roads %>% filter(road_name_type != "Other") %>% mutate(road_name_type = factor(road_name_type, levels = hamilton_top_types)),
          size = 1,
          aes(colour = road_name_type)) +
  scale_colour_manual(values = PALETTE) + 
  geom_richtext(data = hamilton_title, 
                aes(x = x, y = y, label = label),
                hjust = 1, vjust = 1, family = FONT, label.colour = NA,
                size = 24,
                fill = NA, colour = "black") +
  geom_richtext(data = hamilton_legend, 
                aes(x = x, y = y, label = label),
                hjust = 1, vjust = 1, family = FONT, label.colour = NA,
                size = 14,
                fill = NA, colour = "black") +
  geom_richtext(data = hamilton_data_note, 
                aes(x = x, y = y, label = label),
                hjust = 0, vjust = 0, family = FONT, label.colour = NA,
                size = 8,
                fill = NA, colour = "black") +
  geom_richtext(data = hamilton_credit, 
                aes(x = x, y = y, label = label),
                hjust = 1, vjust = 0, family = FONT, label.colour = NA,
                size = 8,
                fill = NA, colour = "black") +
  coord_sf(datum = NA) +
  theme_void() +
  theme(plot.background = element_rect(fill = COL_BG, colour = NA),
        panel.background = element_rect(fill = COL_BG, colour = NA),
        legend.position = "none")

ggsave(plot = gg_hamilton,
       "Day_05/Day_05_hamilton_street_colours.png",
       width = 20, height = 23)