Fundamentals of map design with mapgl

The mapgl package aims to expose the powerful map design capabilities of Mapbox GL JS and Maplibre GL JS, while still feeling intuitive to R users. This means that map-making may require a little more code than other mapping packages - but it also gives you maximum flexibility in how you design your maps.

library(tidycensus)
library(mapgl)

fl_age <- get_acs(
  geography = "tract",
  variables = "B01002_001",
  state = "FL",
  year = 2022,
  geometry = TRUE
)

## Getting data from the 2018-2022 5-year ACS

## Using FIPS code '12' for state 'FL'

fl_map <- mapboxgl(mapbox_style("light")) 

fl_map

Continuous styling

fl_map |> 
  add_fill_layer(
  id = "fl_tracts",
  source = fl_age,
  fill_color = interpolate(
    column = "estimate",
    values = c(20, 80),
    stops = c("lightblue", "darkblue"),
    na_color = "lightgrey"
  ),
  fill_opacity = 0.5
 ) |> 
  add_legend(
    "Median age in Florida",
    values = c(20, 80),
    colors = c("lightblue", "darkblue")
  )

Categorical styling

brewer_pal <- RColorBrewer::brewer.pal(5, "RdYlBu")

fl_map |> 
  add_fill_layer(
  id = "fl_tracts",
  source = fl_age,
  fill_color = step_expr(
    column = "estimate",
    base = brewer_pal[1],
    stops = brewer_pal[2:5],
    values = seq(25, 70, 15),
    na_color = "white"
  ),
  fill_opacity = 0.5
 ) |> 
  add_legend(
    "Median age in Florida",
    values = c(
      "Under 25",
      "25-40",
      "40-55",
      "55-70",
      "Above 70"
    ),
    colors = brewer_pal,
    type = "categorical"
  )

Pop-ups, tooltips, and highlighting

fl_age$popup <- glue::glue(
  "<strong>GEOID: </strong>{fl_age$GEOID}<br><strong>Median age: </strong>{fl_age$estimate}"
)

fl_map |> 
  add_fill_layer(
  id = "fl_tracts",
  source = fl_age,
  fill_color = interpolate(
    column = "estimate",
    values = c(20, 80),
    stops = c("lightblue", "darkblue"),
    na_color = "lightgrey"
  ),
  fill_opacity = 0.5,
  popup = "popup",
  tooltip = "estimate",
  hover_options = list(
    fill_color = "yellow",
    fill_opacity = 1
  )
 ) |> 
  add_legend(
    "Median age in Florida",
    values = c(20, 80),
    colors = c("lightblue", "darkblue")
  )