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Discrete Global Grid Reference Systems

Release: 1st Sept, 2025

Modified on: 15th Sept, 2025
This version:
http://w3id.org/dggrs/v1.0.0
Revision:
v1.0.0
Authors:
Luís Moreira de Sousa, Insituto Superior Técnico, University of Lisbon
Download serialization:
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License:
https://creativecommons.org/licenses/by-nc-nd/4.0/ License
Visualization:
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Provenance of this page
DGGRS Ontology Specification Draft

Abstract

An ontology for Discrete Global Grid Reference Systems (DGGRS). A DGGRS couples a Discrete Global Grid System (DGGS) tesselating the Earth's surface, with a cell indexing scheme. Thus a DGGRS is able to uniquely and unequivocally identify any position on globe, int theory at whatever resolution desired. The DGGRS ontology was developed as part of the GeoPlegma project. It supports a web registry of DGGRS and the different software systems implementing them.

Introduction back to ToC

Defines classes for DGGRS, Indexing mechanism, Polyhdron and DGGRS implementation, plus the relations between them. Catalogues individuals for Polyhedron and Indexing.

DGGRS: Overview back to ToC

This ontology has the following classes and properties.

Classes

Object Properties

Data Properties

Named Individuals

Rules

DGGRS: Description back to ToC

This is a placeholder text for the description of your ontology. The description should include an explanation and a diagram explaining how the classes are related, examples of usage, etc.

Cross-reference for DGGRS classes, object properties and data properties back to ToC

This section provides details for each class and property defined by DGGRS.

Classes

DGGRS implementationc back to ToC or Class ToC

IRI: https://w3id.org/dggrs/ImplDGGRS

A software system implementing a DGGRS. It should at a minimum provide an API to transform a geographic location into a zone (cell) identifier at a given refinement level (resolution), plus its inverse.
is in domain of
implements op

DGGRS indexing mechanismc back to ToC or Class ToC

IRI: https://w3id.org/dggrs/Index

A mathematical function, ordering mechanism, or any other method providing a unique identifier to each zone (cell) of a DGGRS, at any refinement level (resolution).
is in range of
uses index op
has members
9R ni, Generalised Balanced Trenary ni, Z7 ni

Discrete Global Grid Reference System (DGGRS)c back to ToC or Class ToC

IRI: https://w3id.org/dggrs/DGGRS

A Spatial Reference System composed of a Discrete Global Grid System and a zone (cell) indexing mechanism allowing for discrete but precise location on the surface of the Earth.
has super-classes
geosrs spatial reference system c
is in domain of
Base polyhedron of a DGGRS op, DGGRS zone sub-division aperture dp, Shape of zones (cells) in a DGGRS dp, uses index op
is in range of
implements op

Polyhedronc back to ToC or Class ToC

IRI: https://w3id.org/dggrs/Polyhedron

A multi-faceted solid providing a geometric structure to divide a sphere or ellipsoid. The platonic solids are the most commonly used, although alternatives may also be used, such as the truncated icosahedron.
is in range of
Base polyhedron of a DGGRS op
has members
Dodecahedron ni, Hexahedron ni, Icosahedron ni, Tetrahedron ni

Object Properties

Base polyhedron of a DGGRSop back to ToC or Object Property ToC

IRI: https://w3id.org/dggrs/basePolyhedron

Usually a polyhedron on which faces the datum surface is projected for further sub-division.
has domain
Discrete Global Grid Reference System (DGGRS) c
has range
Polyhedron c

implementsop back to ToC or Object Property ToC

IRI: https://w3id.org/dggrs/implements

has domain
DGGRS implementation c
has range
Discrete Global Grid Reference System (DGGRS) c

uses indexop back to ToC or Object Property ToC

IRI: https://w3id.org/dggrs/usesIndex

has domain
Discrete Global Grid Reference System (DGGRS) c
has range
DGGRS indexing mechanism c

Data Properties

DGGRS zone sub-division aperturedp back to ToC or Data Property ToC

IRI: https://w3id.org/dggrs/aperture

The number of zones in the subsequent DGGRS refinement level corresponding to a zone on the current level. Rate of zone sub-division. The higher the number, the ´faster' a DGGRS refines to small zones.
has domain
Discrete Global Grid Reference System (DGGRS) c
has range

Shape of zones (cells) in a DGGRSdp back to ToC or Data Property ToC

IRI: https://w3id.org/dggrs/zoneShape

Usually a regular shape like the hexagon or triangle. May also be a rhombic shape such as the parellelogram.
has domain
Discrete Global Grid Reference System (DGGRS) c
has range
string

Named Individuals

9Rni back to ToC or Named Individual ToC

IRI: https://w3id.org/dggrs/9r

A highly compact index for hexagonal grid systems developed by Ecere and first implemented by DGGAL.
belongs to
DGGRS indexing mechanism c

Dodecahedronni back to ToC or Named Individual ToC

IRI: https://w3id.org/dggrs/dodecahedron

A solid with twelve equal faces which are pentagons.
belongs to
Polyhedron c

Generalised Balanced Trenaryni back to ToC or Named Individual ToC

IRI: https://w3id.org/dggrs/gbt

Indexes hexagonal grid systems of aperture 7. At each refinement level cells rotate circa 20º so that vertices of a cell septet concide with the six vertices of a cell in the previous refinement level.
belongs to
DGGRS indexing mechanism c

Hexahedronni back to ToC or Named Individual ToC

IRI: https://w3id.org/dggrs/hexahedron

A solid with six equal faces which are squares
belongs to
Polyhedron c

Icosahedronni back to ToC or Named Individual ToC

IRI: https://w3id.org/dggrs/icosahedron

A solid with twenty equal faces which are equilateral triangles.
belongs to
Polyhedron c

Tetrahedronni back to ToC or Named Individual ToC

IRI: https://w3id.org/dggrs/tetrahedron

A solid with four equal faces which are equilateral triangles.
belongs to
Polyhedron c

Z7ni back to ToC or Named Individual ToC

IRI: https://w3id.org/dggrs/z7

An index for hexagonal grid systems of aperture 7.
belongs to
DGGRS indexing mechanism c

Rules

Legend back to ToC

c: Classes
op: Object Properties
dp: Data Properties
ni: Named Individuals

References back to ToC

Add your references here. It is recommended to have them as a list.

Acknowledgments back to ToC

The authors would like to thank Silvio Peroni for developing LODE, a Live OWL Documentation Environment, which is used for representing the Cross Referencing Section of this document and Daniel Garijo for developing Widoco, the program used to create the template used in this documentation.