Getting Started with GeoJSON

In this age of digital maps, working with geospatial data is an essential skill. GeoJSON is one of the primary formats for storing this type of data, representing geographic features according to JavaScript Object Notation (JSON). This article provides an overview of GeoJSON and a few practical examples.

What is GeoJSON?

GeoJSON is a lightweight geospatial data interchange format built on JSON for representing geographic features and their attributes. It was developed in 2008 to enable data exchange between web-based services.

GeoJSON can represent points, lines, polygons, and multi-polygons along with their associated properties. It can also represent a geometry (such as an envelope or bounding box) composed of multiple connected components.

GeoJSON appears in many geospatial applications and serves as a standard exchange format for tools that handle location-based data.

Using GeoJSON Data

When working with GeoJSON data, you need to understand both the structure and the different feature types it can represent. The data consists of a collection of features, each carrying multiple properties.

For example, a point feature could include properties for its latitude and longitude, plus its elevation or name.

You also need to understand the coordinate reference system (CRS) behind the data. A CRS describes how coordinates map to real-world locations. GeoJSON files typically use the WGS 84 CRS, though other systems work as well. Knowing which CRS your data uses prevents positioning errors.

Working with GeoJSON

Handling GeoJSON data requires the right tools. Several libraries and applications support this format.

The GDAL library is a popular open source library for manipulating, processing, and converting geospatial data. It reads, writes, and transforms GeoJSON files with ease.

Several web-based applications also let you view GeoJSON data and build custom maps. Mapbox Studio is an online application for designing custom maps from geographic datasets.

Examples of GeoJSON in Action

GeoJSON is a versatile format with a wide range of applications. Here are a few examples:

Digital mapping applications such as Google Maps or Apple Maps use GeoJSON to store map data.
Geospatial analytics applications such as ArcGIS or QGIS can use GeoJSON data to create interactive maps.
Augmented reality applications such as ARCore or ARKit can use GeoJSON to create 3D models of geographical features such as buildings or terrain.
Web applications such as Leaflet or OpenLayers can use GeoJSON to create interactive maps on the web.