Table of extensions to the JSON Schema vocabulary

This table is an attempt to maintain a list of all x-ogc-* JSON Schema vocabulary extensions defined for use by OGC standards.

See the draft OGC API - Features - Part 5: Schemas

and the work done in OGC API - Common which has now been moved out of Part 2, to a proposal for a Part 3?: Schemas: https://github.com/opengeospatial/ogcapi-common/tree/master/proposals/schemas

These are related issues:

• https://github.com/opengeospatial/ogcapi-features/issues/945

• https://github.com/opengeospatial/ogcapi-features/issues/954

• https://github.com/opengeospatial/ogcapi-common/issues/334

• https://github.com/opengeospatial/ogcapi-coverages/issues/173

• https://github.com/opengeospatial/ogcapi-processes/issues/395

For status, using candidate meaning generally agreed upon, and proposed for recent suggestions requiring more discussions.

Keyword	Status	Description
Defined in Features - Part 5: Schemas
x-ogc-role	candidate	Role of a property (e.g., ID, primary geometry/time, reference)
x-ogc-propertySeq	candidate	Sequential order of a property (e.g. for CSV, GeoTIFF)
x-ogc-unit	candidate	Unit of measure (by default in UCUM; URI if unitLang is QUDT)
x-ogc-unitLang	candidate	Alternate language for unit (e.g., QUDT)
x-ogc-definition	candidate	Semantic definition (e.g., QUDT https://qudt.org/vocab/quantitykind/AtmosphericPressure)
x-ogc-collectionId	candidate	A collection ID e.g., if role is reference (NOTE: can be an array)
x-ogc-uriTemplate	candidate	A URI template (e.g., as a way to reference a feature with a {featureId} template)
Defined in OGC API - Common - Part 3? proposal
x-ogc-nullValues	proposed	The values representing no data (array)
Recent proposals
x-ogc-returnedByDefault	deprecated	Set to false if property is not returned by default (default: true) — we decided to list these in a property of the collection description instead
Proposed for OGC API - Coverages
x-ogc-resolution	proposed	Resolution for each dimension (in units of the dimension) applying to this particular field (e.g., higher panchromatic band resolution, lower scene classification layer)
x-ogc-statistics	proposed	An object with statistics for this field: min, max, average, stdDev
x-ogc-variableType	proposed	The type of variable (continuous, categoricalOrdinal, categoricalNominal, numericalOrdinal, numericalNominal), which notably provides context about proper interpolation methods (see also Common - Part 2 UML Diagram)
Proposed for OGC API - Coverages (from OMS)
x-ogc-observingProcedure	proposed	(as defined by OMS)
x-ogc-observer	proposed	(as defined by OMS)
x-ogc-featureOfInterest	proposed	(as defined by OMS)
x-ogc-platform	proposed	(as defined by SOSA, OMS)