The Open Geospatial Consortium (OGC) announces the release of the OGC Features and Geometries JSON (JSON-FG) Standard.

The Standard extends the GeoJSON format to support additional capabilities that are out of scope for GeoJSON but are important for a variety of geospatial feature data use cases.

Overview

GeoJSON is a widely adopted exchange format for feature data and is broadly supported across geospatial applications, including most implementations of the OGC API – Features – Part 1: Core Standard.

However, GeoJSON has intentional restrictions that prevent or limit its use in certain geospatial application contexts. For example, GeoJSON is restricted to the use of WGS 84 coordinates in longitude-latitude axis order, supports only the original Simple Features geometry types, and does not provide a mechanism for classifying features according to type.

What JSON-FG Adds

The OGC Features and Geometries JSON (JSON-FG) Standard defines a set of GeoJSON extensions that provide standardized approaches for addressing these and other requirements.

The goal of JSON-FG is to support capabilities that may require some geospatial expertise but are broadly useful across many applications. Edge cases are considered out of scope for the Standard.

Mandatory Extensions

The JSON-FG Standard specifies the following mandatory extensions to the GeoJSON format:

  • The ability to use Coordinate Reference Systems (CRSs) other than WGS 84 with longitude-latitude axis order;
  • The ability to encode temporal characteristics of a feature; and
  • A statement identifying the JSON-FG conformance classes supported by a JSON-FG feature collection, feature, or geometry.

Optional Extensions

The Standard also specifies the following optional extensions:

  • Support for solids and prisms as geometry types;
  • Support for circular arcs, compound curves, and curve polygons as geometry types;
  • Support for measure values in coordinates; and
  • The ability to declare the type and schema of a feature.

Compatibility with GeoJSON

Geographic features, their properties, and their spatial extents that can be represented as GeoJSON objects continue to be encoded as GeoJSON.

Additional information not specified in the GeoJSON RFC is mainly encoded in additional members of the GeoJSON objects. These additional members use keys that do not conflict with existing GeoJSON keys, enabling existing and future GeoJSON clients to continue parsing and understanding GeoJSON content successfully.

Clients that support JSON-FG can additionally parse and interpret the extended members.

The syntax of JSON-FG is formally specified using JSON Schema.

As with all OGC Standards, the OGC Features and Geometries JSON (JSON-FG) Standard is freely available to download and implement.

About OGC

The Open Geospatial Consortium (OGC) is a membership organization dedicated to using the power of geography and technology to solve problems faced by people and the planet. OGC unlocks value and opportunity for its members through Standards, Innovation, and Collaboration.

OGC’s membership represents a diverse and active global community drawn from government, industry, academia, international development agencies, research and scientific organizations, civil society, and advocates.

Visit ogc.org for more information about OGC’s work.