Crate jsonfg 

Types for OGC Features and Geometries JSON (JSON-FG), the OGC extension of GeoJSON standardized as OGC 21-045r1 (version 1.0).

JSON-FG is a strict superset of GeoJSON. It adds, as GeoJSON foreign members, the ability to convey:

• geometry in a coordinate reference system other than WGS 84, via the place member and coordRefSys;
• geometry types beyond GeoJSON: solids (Geometry::Polyhedron, Geometry::Prism, …) and curves (Geometry::CircularString, Geometry::CurvePolygon, …);
• temporal information via time;
• feature classification via featureType and featureSchema.

This crate is the JSON-FG counterpart to the geojson crate: a serde-based data model, with no I/O or content-negotiation logic. Enable the geojson feature for conversions to and from geojson::Geometry.

Example

use jsonfg::{conformance, CoordRefSys, Feature, Geometry};

// A feature whose geometry is a point in a projected CRS (EPSG:3857): the native
// geometry goes in `place`, and `geometry` (the GeoJSON member) is left null.
let mut feature = Feature::new();
feature.conforms_to = Some(vec![conformance::CORE.to_owned()]);
feature.coord_ref_sys = Some(CoordRefSys::from_epsg(3857));
feature.place = Some(Geometry::point(vec![100.0, 200.0]));

let json = serde_json::to_value(&feature).unwrap();
assert_eq!(json["place"]["type"], "Point");
assert!(json["geometry"].is_null());

Modules

conformance

Conformance-class URIs and the JSON-FG media type.

Structs

Feature

A JSON-FG feature.

FeatureCollection

A JSON-FG feature collection.

GeometryMeta

Optional members common to every JSON-FG geometry object.

Measures

Declares that positions in a geometry carry a trailing measure (m) value, and optionally describes it.

Reference

A {"type": "Reference", "href": …, "epoch": …} coordinate reference system object.

Time

The value of a feature’s time member: a temporal instant (as a date and/or a timestamp) and/or an interval. At least one member must be present.

Enums

CoordRefSys

The value of a coordRefSys member: a single reference, or (for a compound CRS) an array of at least two references.

FeatureCollectionKind

Marker for the type member of a FeatureCollection; always serializes as "FeatureCollection".

FeatureKind

Marker for the type member of a Feature; always serializes as "Feature".

FeatureSchema

The value of the featureSchema member: a single schema URI, or a map from feature type name to schema URI (for multi-typed features).

FeatureType

The value of the featureType member: a single classifier, or several.

Geometry

A JSON-FG geometry.

Id

A feature identifier: a string or a number.

RefSys

A single coordinate reference system: either a plain URI, or a by-reference object that may pin a dynamic CRS to an epoch.

ReferenceKind

Marker for the type member of a Reference; always serializes as "Reference".

Constants

CRS84

The OGC URI for WGS 84 longitude/latitude (2D), the JSON-FG default CRS.

CRS84H

The OGC URI for WGS 84 longitude/latitude/height (3D).

UNBOUNDED

The marker used for an unbounded end of a time Time::interval.

Type Aliases

Bbox

A bounding box: four numbers (2D) or six numbers (3D).

JsonObject

A JSON object: an ordered map of string keys to arbitrary JSON values. Used for feature properties and for preserved foreign members.

Position

A single coordinate: [x, y], [x, y, z], or [x, y, z, m] (the trailing m value requires the Measures conformance class).