GeoJSON is an open standard format for encoding geographic data structures using JSON (JavaScript Object Notation). It is the most widely used format for sharing geographic data on the web.
Why GeoJSON?
GeoJSON is human-readable, widely supported, and works natively with web technologies. It can be opened in a text editor, processed with standard JSON tools, and displayed directly in web mapping libraries like Leaflet and Mapbox.
GeoJSON Structure
A GeoJSON file contains a FeatureCollection, which is a list of Features. Each Feature has a geometry (the shape and location) and properties (attributes). Coordinates are stored as [longitude, latitude] pairs.
Geometry Types
- Point — a single location such as a business or sensor
- LineString — a sequence of points forming a line such as a road or river
- Polygon — a closed shape such as a building footprint or neighbourhood boundary
- MultiPoint, MultiLineString, MultiPolygon — collections of the above types
GeoJSON uses [longitude, latitude] order, which is the opposite of the conventional (latitude, longitude) order. This is a common source of confusion. Always check coordinate order when working with GeoJSON data.
Working with GeoJSON
GeoJSON files can be opened in QGIS, viewed on geojson.io, and processed with Python libraries like Fiona and Shapely. Most Canadian open data portals offer GeoJSON as a download format.
Learn about the other major GIS format in Shapefiles Explained.