In this chapter, you learned how to add and style a GeoJSON layer in Leaflet.js. Finally, you learned how to iterate through the features in a GeoJSON file and perform an action such as binding a pop up or applying a style based on a property in the feature. GeoJSON is a popular and common data format. Knowing how to use it in Leaflet.js is an important skill. This chapter gave you a solid foundation with which you can continue to learn about GeoJSON.

In the next chapter, you will learn how to create heatmaps using several available plugins.