Skip to main content

GeoJSON

GeoJSON represents vector features as JSON. It is simple to read, widely supported by web mapping libraries and common in APIs.

A feature contains geometry plus a properties object. That makes it excellent for small/medium web datasets and interchange.

CRS convention​

Modern GeoJSON uses WGS84-style longitude/latitude coordinates and no longer relies on custom embedded CRS objects in the way older GeoJSON variants did. Reproject NZTM data to EPSG:4326 for ordinary web GeoJSON exchange unless the receiving system explicitly specifies otherwise.

Watch file size​

JSON is verbose. A national parcel layer as GeoJSON can be enormous and inefficient compared with GeoPackage, FlatGeobuf, database/service or vector tiles.

Good uses​

  • API responses
  • small web-map layers
  • hand-inspectable interchange
  • generated research outputs

For a working local database use GeoPackage.

Last reviewed: 26 August 2026

Last updated on