Is it [lat, lng] or [lng, lat] in GeoJSON?

Always [longitude, latitude], optionally followed by altitude. Leaflet's L.latLng uses the opposite order, which is a common source of mistakes.

Why does my GeoJSON show up in the wrong place?

Usually because latitude and longitude are swapped, or the coordinates are in a projected system such as UTM instead of WGS 84 degrees.

GeoJSON Format Explained: Structure, Coordinates and Examples

GeoJSON is a JSON format for geographic features: points, lines and polygons with their attributes. It is the standard format for web maps and is read natively by Leaflet, Mapbox, OpenLayers, D3, QGIS and most GIS software. GitHub even renders .geojson files as maps.

The current specification is RFC 7946, published by the IETF in 2016.

Example: A FeatureCollection with one point

{
  "type": "FeatureCollection",
  "features": [
    {
      "type": "Feature",
      "properties": { "name": "Brandenburg Gate", "built": 1791 },
      "geometry": {
        "type": "Point",
        "coordinates": [13.377704, 52.516275]
      }
    }
  ]
}

Convert GeoJSON files

Convert GeoJSON to KML— Convert a GeoJSON file to KML for Google Earth
Convert GeoJSON to Shapefile— Convert a GeoJSON file to a Shapefile ZIP (.shp, .shx, .dbf, .prj)
Convert GeoJSON to GPX— Convert a GeoJSON file to a GPS track/route file
Convert GeoJSON to CSV (lat/lng)— Extract Point features from GeoJSON to a lat/lng CSV
Convert GeoJSON to TopoJSON— Convert GeoJSON to compact TopoJSON with shared borders for D3 and web maps
Convert GeoJSON to SVG map— Render GeoJSON geometry as a standalone SVG map
Convert GeoJSON to WKT— Convert GeoJSON geometry/features to WKT text
Convert GeoJSON to KMZ— Convert a GeoJSON file to a compressed KMZ archive for Google Earth
Convert Shapefile to GeoJSON— Convert a Shapefile ZIP (.shp + .dbf) to GeoJSON
Convert KML to GeoJSON— Convert a KML map file to GeoJSON
Convert GPX to GeoJSON— Convert a GPS track/route file to GeoJSON
Convert CSV to GeoJSON— Convert a CSV with latitude and longitude columns to a GeoJSON FeatureCollection
Convert TopoJSON to GeoJSON— Convert TopoJSON topology objects to GeoJSON features
Convert WKT to GeoJSON— Parse Well-Known Text geometry into a GeoJSON FeatureCollection

Geometry types

A Feature wraps one geometry together with a properties object for its attributes, and a FeatureCollection holds a list of features.

Point and MultiPoint
LineString and MultiLineString
Polygon and MultiPolygon: the first ring is the outer boundary, any further rings are holes
GeometryCollection: a mix of geometries

Coordinate rules that trip people up

Order is [longitude, latitude], the reverse of how coordinates are usually spoken
RFC 7946 GeoJSON is always WGS 84 longitude/latitude. The older "crs" member was removed from the standard, so projected coordinates (for example UTM metres) are not valid GeoJSON
Polygon rings must be closed: the last position repeats the first
Exterior rings should run counter-clockwise and holes clockwise (the right-hand rule)
Six decimal places is about 10 cm of precision, enough for almost all uses; more digits only make the file bigger

GeoJSON vs TopoJSON, KML and Shapefile

TopoJSON: stores shared borders once, so files with neighbouring polygons are much smaller; common with D3
KML: XML with styling, made for Google Earth
Shapefile: the traditional desktop GIS format, a set of files with strict field limits

How to open a GeoJSON file

geojson.io: view and edit in the browser
QGIS: drag the file into the map
GitHub: commit a .geojson file and open it to see a map
Any text editor or JSON viewer

Frequently Asked Questions

Is it [lat, lng] or [lng, lat] in GeoJSON?: Always [longitude, latitude], optionally followed by altitude. Leaflet's L.latLng uses the opposite order, which is a common source of mistakes.
Why does my GeoJSON show up in the wrong place?: Usually because latitude and longitude are swapped, or the coordinates are in a projected system such as UTM instead of WGS 84 degrees.