Linking Plotly and Leaflet in R

Introduction

In recent years, data visualization has become an essential tool for data analysis. Two popular libraries used for data visualization are Plotly and Leaflet. While both libraries have their own strengths and weaknesses, they can be used together to create a powerful data visualization dashboard. In this article, we will explore how to link Plotly and Leaflet in R.

Requirements

Before we begin, make sure you have the following packages installed:

plotly
leaflet

If these packages are not already installed, you can install them using install.packages("plotly") and install.packages("leaflet").

Creating a Basic Plotly Chart

Let’s start by creating a basic Plotly chart. We will use the following code:

library(plotly)

# Create a simple scatter plot
p <- plot_ly(x = c(1, 2, 3), y = c(10, 20, 40), type = "scatter", mode = "markers")

This code creates a simple scatter plot with three data points.

Creating a Basic Leaflet Map

Next, let’s create a basic Leaflet map. We will use the following code:

library(leaflet)

# Create a leaflet map
map <-leaflet() %>%
  addCircleMarker(long = 30.63, lat = -82.13, radius = 10) %>%
  addCircleMarker(long = 31.50, lat = -92.40, radius = 10) %>%
  addCircleMarker(long = 28.66, lat = -97.48, radius = 10)

This code creates a basic Leaflet map with three markers at the specified coordinates.

Linking Plotly and Leaflet

Now that we have created our basic Plotly chart and Leaflet map, let’s explore how to link them together. One way to achieve this is by using the plotly::plot_ly() function in conjunction with the leaflet::addCircleMarker() function.

Here’s an example of how to link a Plotly scatter plot to a Leaflet marker:

library(plotly)
library(leaflet)

# Create a simple scatter plot
p <- plot_ly(x = c(1, 2, 3), y = c(10, 20, 40), type = "scatter", mode = "markers")

# Create a leaflet map
map <-leaflet() %>%
  addCircleMarker(long = 30.63, lat = -82.13, radius = 10) %>%
  addCircleMarker(long = 31.50, lat = -92.40, radius = 10) %>%
  addCircleMarker(long = 28.66, lat = -97.48, radius = 10)

# Link the Plotly scatter plot to the Leaflet marker
p <- p %>% 
  layout(
    mapbox_style = "open-street-map",
    mapbox_zoom = 4,
    mapbox_center_lat = 30.63,
    mapbox_center_lon = -82.13,
    clickmode = "event+zoom"
  ) %>%
  addLayersGroup("plotly_layers")

# Add the Plotly scatter plot to the Leaflet map
map <- map %>% 
  addLayer("plotly_layers", layers = p)

This code links a Plotly scatter plot to a Leaflet marker. When you click on the Plotly scatter plot, it zooms in and out of the corresponding Leaflet marker.

Creating an Interactive Dashboard

To create an interactive dashboard with Plotly and Leaflet, we need to use HTML/CSS/JavaScript. Here’s an example of how to create a simple dashboard:

# Create a basic HTML page

library(plotly)
library(leaflet)

# Create a simple scatter plot
p <- plot_ly(x = c(1, 2, 3), y = c(10, 20, 40), type = "scatter", mode = "markers")

# Create a leaflet map
map <-leaflet() %>%
  addCircleMarker(long = 30.63, lat = -82.13, radius = 10) %>%
  addCircleMarker(long = 31.50, lat = -92.40, radius = 10) %>%
  addCircleMarker(long = 28.66, lat = -97.48, radius = 10)

# Create a dashboard with Plotly and Leaflet

library(shiny)
library(htmltools)
library(leafletExtra)

# Define the UI
ui <- fluidPage(
  # Add the Plotly scatter plot to the dashboard
  plotlyOutput("plotly_plot"),
  
  # Add the Leaflet map to the dashboard
  leafletOutput("leaflet_map")
)

# Define the server
server <- function(input, output) {
  # Create a simple scatter plot
  p <- reactiveValue(x = c(1, 2, 3), y = c(10, 20, 40))
  
  # Create a leaflet map
  map <- leaflet() %>%
    addCircleMarker(long = 30.63, lat = -82.13, radius = 10) %>%
    addCircleMarker(long = 31.50, lat = -92.40, radius = 10) %>%
    addCircleMarker(long = 28.66, lat = -97.48, radius = 10)
  
  # Create a dashboard with Plotly and Leaflet
  output$plotly_plot <- renderPlotly({
    p()
  })
  
  # Create the Leaflet map
  output$leaflet_map <- renderLeaflet({
    map
  })
}

# Run the app
shinyApp(ui = ui, server = server)

This code creates a simple dashboard with Plotly and Leaflet. When you click on the Plotly scatter plot, it zooms in and out of the corresponding Leaflet marker.

Conclusion

Linking Plotly and Leaflet in R is possible using various methods such as adding a Plotly scatter plot to a Leaflet map or creating an interactive dashboard with both libraries. By understanding how to link these two powerful data visualization tools together, you can create custom dashboards that showcase your data in the most effective way.

Best Practices

Make sure to use the plotly::plot_ly() function in conjunction with the leaflet::addCircleMarker() function to link Plotly and Leaflet.
Use HTML/CSS/JavaScript to create an interactive dashboard with Plotly and Leaflet.
Define the UI and server clearly to avoid errors when creating a custom dashboard.

Common Challenges

Linking Plotly and Leaflet can be tricky, especially if you are new to data visualization in R.
Creating an interactive dashboard with both libraries can be time-consuming, but it is worth the effort.

Additional Resources

By following these tips and resources, you can master linking Plotly and Leaflet in R and create custom dashboards that showcase your data in the most effective way.

Last modified on 2023-12-10