Geographical Data Visualization is a Snap using Leaflet

The Leaflet package is the de facto package for creating interactive maps in R. There is little wonder why. Dynamic, intuitive and yielding pleasant results, it scratches an itch that R users had for a long time. It can help create maps that inform, guide decisions, and in some cases even entertain.

Some of its Amazing Features

• Interactive panning/zooming
• Compose maps using unique combinations of:
• Map tiles
• Markers
• Polygons
• Lines
• Popups
• GeoJSON capability

You can also create maps right from the R console, RStudio or other IDE.

• Embed the maps in knitr/R Markdown documents and Shiny apps
• Easily render spatial objects from the sp or sf packages, or data frames with latitude/longitude columns
• Utilize map bounds and mouse events to drive Shiny logic
• Display maps in non-spherical mercator projections. This means mapping of ellipsoidal latitude and longitude coordinates onto a plane without it wrapping around a sphere, and thus showing accurate relative landmass sizes
• Augment map features using chosen plugins from leaflet plugins repository

To install this R package, run this command at your R prompt:

install.packages('leaflet','magrittr')

library(leaflet)

library(magrittr)

Once you have installed and loaded it, you can use this package at the R console, within R Markdown documents, and within Shiny applications.

You create a Leaflet map with these basic steps:

1. Create a map widget by calling leaflet().
2. Add layers (i.e., features) to the map by using layer functions (e.g. addTiles, addMarkers, addPolygons) to modify the map widget.

Notice how this logic is similar to the “grammar of graphics.” If you are already using ggplot, leaflet ends up being very intuitive.