I.  Abstract

GeoSciML (Geoscience Markup Language) is a Standard for representing geological features commonly described and portrayed in geological maps, cross sections, geological reports and databases. The Standard is composed of multiple parts. Part 1 describes a logical model, which was originally developed by the IUGS CGI (Commission for the Management and Application of Geoscience Information). Part 3 (this document) describes encoding rules for the exchange of geological map data, geological time scales, boreholes, and metadata for laboratory analyses. The encoding rules define an application of Features and Geometry JSON, also known as JSON-FG.

III.  Preface

The primary goal of this specification is to capture the schema, and encoding syntax of key elements described and portrayed in geological maps and databases, in order to enable information systems to interoperate with such data.

1.  Scope

Part 3 of GeoSciML covers the representation in JSON of features from the domain of geology (earth materials, geological units and stratigraphy, geological time, geological structures, geomorphology, geochemistry) and sampling features common to the practice of geoscience, such as boreholes and geological specimens.

2.  Conformance

This standard defines a JSON encoding which conforms to the OGC JSON-FG 1.0 encoding rules.

Requirements for one standardization target type are considered:

The normative artefacts for JSON encoding are the JSON Schema files provided online with this specification. Those documents explicitly provide the requirements that must be met by any JSON instance document claiming compliance to this specification. Any requirements that cannot be expressed in JSON Schema are described in the relevant section of this document. Therefore, compliant JSON instances shall:

Conformance with this standard shall be checked using all the relevant tests specified in Annex A (normative) of this document. The framework, concepts, and methodology for testing, and the criteria to be achieved to claim conformance are specified in the OGC Compliance Testing Policies and Procedures and the OGC Compliance Testing web site.

All requirements-classes and conformance-classes described in this document are owned by the standard(s) identified.

3.  Normative references

The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

ISO: ISO/TS 19103:2005, Geographic information — Conceptual schema language. International Organization for Standardization, Geneva (2005). https://www.iso.org/standard/37800.html.

ISO: ISO 19107:2003, Geographic information — Spatial schema. International Organization for Standardization, Geneva (2003). https://www.iso.org/standard/26012.html.

ISO: ISO 19108:2002/Cor 1:2006, Geographic information — Temporal schema — Technical Corrigendum 1. International Organization for Standardization, Geneva (2002). https://www.iso.org/standard/44883.html.

ISO: ISO 8601, Data elements and interchange formats — Information interchange — Representation of dates and times. International Organization for Standardization, Geneva https://www.iso.org/standard/40874.html.

ISO: ISO 19156:2011, Geographic information — Observations and measurements. International Organization for Standardization, Geneva (2011). https://www.iso.org/standard/32574.html.

ISO: ISO 19111:2007, Geographic information — Spatial referencing by coordinates. International Organization for Standardization, Geneva (2007). https://www.iso.org/standard/41126.html.

ISO: ISO 19115:2003, Geographic information — Metadata. International Organization for Standardization, Geneva (2003). https://www.iso.org/standard/26020.html.

ISO: ISO 19101:2002, Geographic information — Reference model. International Organization for Standardization, Geneva (2002). https://www.iso.org/standard/26002.html.

Simon Cox: OGC 10-025r1, Observations and Measurements — XML Implementation. Open Geospatial Consortium (2011). https://docs.ogc.org/is/10-025r1/10-025r1/pdf.

T. Berners-Lee, R. Fielding, L. Masinter: IETF RFC 3986, Uniform Resource Identifier (URI): Generic Syntax. RFC Publisher (2005). https://www.rfc-editor.org/info/rfc3986.

OMG: Unified Modeling Language (UML). Version 2.3

INSPIRE Thematic Woring Group Geology: INSPIRE Data Specification for the spatial data theme Geology Version 3.0. European Commission Joint Research Centre (2013)

Clemens Portele, Panagiotis (Peter) A. Vretanos: OGC 21-045r1, OGC Features and Geometries JSON — Part 1: Core. Open Geospatial Consortium (2026). http://www.opengis.net/doc/IS/json-fg-1/1.0.

ISO: ISO 19101-1:2014, Geographic information — Reference model — Part 1: Fundamentals. International Organization for Standardization, Geneva (2014). https://www.iso.org/standard/59164.html.

4.  Terms and definitions

This document uses the terms defined in OGC Policy Directive 49, which is based on the ISO/IEC Directives, Part 2, Rules for the structure and drafting of International Standards. In particular, the word “shall” (not “must”) is the verb form used to indicate a requirement to be strictly followed to conform to this document and OGC documents do not use the equivalent phrases in the ISO/IEC Directives, Part 2.

This document also uses terms defined in the OGC Standard for Modular specifications (OGC 08-131r3), also known as the ‘ModSpec’. The definitions of terms such as standard, specification, requirement, and conformance test are provided in the ModSpec.

For the purposes of this document, the following additional terms and definitions apply.

abstraction of real world phenomena

[SOURCE: ISO 19101-1:2014]

set of features from a dataset

[SOURCE: ISO 19168-1:2020]

an information resource (series of octets) described by the “application/json” media type [JSON Schema 2020-12]

[SOURCE: OGC 21-045r1]

an unordered set of name/value pairs mapping the name to a JSON value [JSON Schema 2020-12, modified]

a JSON document that contains a JSON-FG root object

[SOURCE: OGC 21-045r1]

a JSON object that validates against the JSON-FG feature schema

[SOURCE: OGC 21-045r1]

a JSON object that validates against the JSON-FG feature collection schema

[SOURCE: OGC 21-045r1]

a JSON object that validates against the JSON-FG geometry schema

[SOURCE: OGC 21-045r1]

a JSON object that is either a JSON-FG feature, a JSON-FG feature collection, or a JSON-FG geometry

[SOURCE: OGC 21-045r1]

a JSON-FG object that is not a direct children of another JSON-FG object

[SOURCE: OGC 21-045r1]

the name of a member

[SOURCE: OGC 21-045r1]

a name/value pair in a JSON object

[SOURCE: OGC 21-045r1]

5.  Conventions

This section provides details and examples for any conventions used in the document. Examples of conventions are symbols, abbreviations, use of JSON schema, or special notes regarding how to read the document.

6.  JSON Encoding Requirement classes (Normative)

JSON Schema files were derived from the UML model following the OGC Best Practice for UML to JSON Encoding Rules (OGC 24-017r1).

Figure 1 — JSON Encoding requirements classes dependencies (external dependencies not shown)

        "material": {
          "type": "Feature",
          "featureType": "RockMaterial",
          "id": "hervey-group-mudstone",
          "geometry": null,
          "properties": {
            "lithology": "http://resource.geosciml.org/classifier/cgi/simplelithology/mudstone"
          }
        }

{
  "type": "Feature",
  "id": "http://example.org/feature/asc/geologicunit/stratno/25947",
  "featureType": "GeologicUnit",
  "geometry": null,
  ...
}

"properties": {
    "time": ["2025-07-10T08:00:00Z", "2025-07-10T18:00:00Z"],
}

"properties": {
    "time": ["2026-07-10T08:00:00-03:30", "2026-07-10T18:00:00-03:30"],
}

7.  Media Types for any data encoding(s)

GeoSciML 5.0 data conforming to the logical model defined in Part 1 of GeoSciML can be encoded in documents conforming to JSON-FG.  The standard MIME-type and sub-type for JSON-FG data should be used to indicate the encoding in internet exchange, as specified in OGC 21-045r1,_ namely

application/geo+json

Bibliography

[1]  ISO: ISO 19168-1:2020, Geographic information — Geospatial API for features — Part 1: Core. International Organization for Standardization, Geneva (2020). https://www.iso.org/standard/32586.html.