Combining {ggmaps}, {terra} and {tidyterra} to produce raster maps.

Using {tidyverse} methods on images from Stadia Maps and Stamen Maps using {ggmap} by functions from {terra} and {tidyterra}

Background

……………………………….

# Load spatial and environmental datasets.
library(ggmap)

# Handle, analyze, and visualize raster and vector data.
library(terra)

# Handling simple features in R
library(sf)

# Tidy data workflows with 'terra' objects.
library(tidyterra)

# Data manipulation, visualization, and wrangling.
library(tidyverse)

# Compiling plots
library(patchwork)


sysfonts::font_add_google("Fira Sans", "body_font")
showtext::showtext_auto()
theme_set(
  theme_minimal(
    base_family = "body_font",
    base_size = 14
  ) +
    theme(
      plot.title = element_text(
        size = 18
      )
    )
)

Getting a raster map from {ggmap}

# Register your Stadia Maps key and enter it here
# register_stadiamaps("you-key-here")

# Get basic data on Boroughs of London
london_sf_map <- spData::lnd |> 
  janitor::clean_names() |> 
  select(name, geometry)

g1 <- london_sf_map |> 
  ggplot(aes(fill = name)) +
  geom_sf(colour = "white") +
  labs(
    title = "Basic Map of London Boroughs",
    subtitle = "From {spData} object `lnd`"
  ) +
  theme(
    legend.position = "none"
  )

london_sf_boundary <- london_sf_map |> 
  st_union()

g2 <- london_sf_boundary |> 
  ggplot() +
  geom_sf() +
  labs(
    title = "Outer boundary map of London",
    subtitle = "Using sf::st_union()"
  )

g <- g1 + g2 +
  plot_annotation(
    tag_levels = "a"
  )

ggsave(
  plot = g,
  filename = here::here("geocomputation", "images",
                        "ggmaps_with_tidyterra_1.png"),
  width = 1200,
  height = 600,
  units = "px"
)

Displaying the basic data (a) Boroughs of London and (b) Outer boundary map of London

Getting {ggmap} data on the boroughs of london

# Bounding Box of London Boundary Map
london_bbox <- st_bbox(london_sf_boundary)

# Convert bbox to a format the {ggmap} understands
names(london_bbox) <- c("left", "bottom", "right", "top")

raw_raster_map <- get_stadiamap(
  bbox = london_bbox,
  zoom = 10,
  maptype = "stamen_toner_lines"
)

class(raw_raster_map)

bbox_raster <- raw_raster_map |> 
  terra::as.raster() |> 
  rast()

g1 <- ggmap(raw_raster_map) +
  labs(
    x = NULL, y = NULL,
    title = "{ggmap} raster: `Stamen Toner Lines` Maptype",
    subtitle = "Using ggmap::ggmap()"
  )

g1

ggplot() +
  geom_spatraster_rgb(data = bbox_raster)

ggsave(
  plot = g,
  filename = here::here("geocomputation", "images",
                        "ggmaps_with_tidyterra_1.png"),
  width = 1200,
  height = 600,
  units = "px"
)