5 Combining interactivity with multiple ggplots

Published

2025-08-29

Combining the patchwork and ggiraph packages makes a nice interactive display of data.

The austria_region.geojson was downloaded from simplemaps SimpleMaps (2025) .

# Load required libraries
library(sf)

Linking to GEOS 3.12.1, GDAL 3.8.4, PROJ 9.4.0; sf_use_s2() is TRUE

library(ggplot2)
library(ggiraph)
library(patchwork)

# Load Austria GeoJSON from SimpleMaps (assumed downloaded locally)
austria_map <- st_read("data/austria_regions.geojson")

Reading layer `austria_regions' from data source 
  `/__w/ggplot2-snippets/ggplot2-snippets/snippets/data/austria_regions.geojson' 
  using driver `GeoJSON'
Simple feature collection with 9 features and 3 fields
Geometry type: MULTIPOLYGON
Dimension:     XY
Bounding box:  xmin: 9.521155 ymin: 46.37864 xmax: 17.14834 ymax: 49.00977
Geodetic CRS:  WGS 84

# Mock population data for each region
population_data <- data.frame(
    region = c(
        "Burgenland", "Kärnten", "Niederösterreich", "Oberösterreich", "Salzburg",
        "Steiermark", "Tirol", "Vorarlberg", "Wien"
    ),
    population = c(294000, 560000, 1680000, 1490000, 560000, 1240000, 760000, 400000, 1900000)
)

# Merge population data with spatial data
austria_map <- merge(austria_map, population_data, by.x = "name", by.y = "region")

# Add a shared data_id for interactivity
gg1 <- ggplot(austria_map) +
  geom_sf_interactive(aes(
    fill = population,
    tooltip = paste(name, "Population:", population),
    data_id = name  # shared ID
  )) +
  scale_fill_gradient(low = "red", high = "green")

gg2 <- ggplot(austria_map, aes(x = reorder(name, population), y = population, fill = population)) +
  geom_bar_interactive(
    stat = "identity",
    aes(tooltip = paste(name, "Population:", population), data_id = name)  # same ID
  ) +
  scale_fill_gradient(low = "red", high = "green") + 
  labs(
    x = "Region",
    y = "Population",
    fill = "Population"
  ) +
  theme(axis.text.x = element_text(angle = 45, hjust = 1))

# Combine plots
gg <- (gg1 / gg2) + plot_annotation(title = "Austria Regions - Interactive Population Overview")

# Wrap with girafe to enable interactivity
girafe(
  ggobj = gg,
  options = list(
    opts_hover(css = "fill:blue;stroke:blue;cursor:pointer;")
  )
)