Book Review: Leaflet.js Essentials by Paul Crickard III

This is a review of Leaflet.js Essentials by Paul Crickard III.


  • Chapter 1 introduces creating a basic map from scratch with leaflet, how to use map tiles, how to create popups, and how to enable geolocation.
  • Chapter 2 shows how to create GeoJSON data, how to style GeoJSON layers by type (LineString, Polygon, etc.), and how to filter to display only a subset of the data.
  • Chapter 3 introduces the leaflet.heat plugin for density heat maps and the heatmap.js library for intensity heat maps. It also teaches how to style and animate heat maps, how to create choropleths, and how to use buttons outside the map to change what's shown in the map.
  • Chapter 4 introduces how to create custom markers and marker shadows as well as several markers that are available online. We also learn how to cluster markers, animate markers, and create pie or bar chart markers.
  • Chapter 5 shows how to use many ESRI resources in Leaflet, including map tiles, shapefiles, and geocoding.
  • Chapter 6 introduces using Node.JS, Python, and C# with leaflet, including getting data via AJAX calls, using MongoDB to save created map points, and creating desktop applications with C#.


This is a very well laid-out, detailed guide to Leaflet. It is intended for complete newbies to Leaflet, but it provides some very advanced information as well. The book claims you should have some JavaScript knowledge before beginning, but I'm not entirely sure this is necessary, since Leaflet maps rely on only very minimal JavaScript.

I enjoyed the breadth of this book. I think the book does a great job of covering the information a beginner would need. It also provides information on a wide variety of topics like good tips for designing for mobile, a very comprehensive list of map tiles (many of these I did not know about), and information on several JavaScript libraries and Leaflet plug-ins that allow for additional functionality within the maps.

On the other hand, there is one major criticism I have with this book, especially for a beginner audience. I'm not that happy with the included code samples or how they are organized. This may just be personal preference, but I prefer books that have the "before this section" code and the "after this section" code so you can start with the before and then double-check with the after if you made an error or didn't understand something. I feel like the provided code samples made it difficult to follow along with programming while reading.

All in all, I wouldn't hesitate to recommend this book to someone beginning to learn Leaflet. For more advanced Leaflet users, there are some gems that may or may not make the book a worthwhile purchase. I will say that I use Leaflet almost every day, and I did learn several things from reading Leaflet.js Essentials.

4 out of 5 stars

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