ISO/DTS 19123-4

• Abstract:

  This document specifies fundamental models of tiling schemas that are suitable for binding tiled imagery and gridded data based on ISO 19163-1 and coverage models based on ISO 19123-1.Except grid coverage, the specified tiling schema may also apply to other coverage types, such as point clouds and general meshes, as long as these types are bound to a gridded space and the corresponding tiling schema is described in the gridded space for these data types.

• Status: Not Published
• ICS: 35.240.70 - IT applications in science
• Technical Committee: ISO/TC 211 - Geographic information/Geomatics
• Drafting Committee: ISO/TC 211/WG 6 - Imagery
• Current Stage: 5020 - FDIS ballot initiated: 2 months. Proof sent to secretariat
• Start Date: 23-Jul-2026
• Completion Date: 23-Jul-2026

• Consolidates: ISO/TR 15969:2021 - Surface chemical analysis — Depth profiling — Measurement of sputtered depth
• Effective Date: 22-Jun-2024

ISO/DTS 19123-4 is an ISO draft technical specification in the Geographic information - Schema for coverage geometry and functions series. It specifies a tiling schema for binding tiled grid space and coverage models based on ISO 19123-1. In practice, it gives a common way to describe tiled imagery, gridded data, and some other coverage types, including point clouds and general meshes, when they are bound to a gridded space.

What does ISO/DTS 19123-4 specify?

ISO/DTS 19123-4 specifies fundamental models for tiling schemas. The focus is on multi-dimensional hyperrectangles, so the document is aimed at rectangular, axis-based tiling rather than other partition shapes.

The schema is intended for tiled imagery and gridded data based on ISO/TS 19163-1 and coverage models based on ISO 19123-1. It can also be applied to other coverage types such as point clouds and general meshes when those data are bound to a gridded space and described there.

The document is organized into clauses for scope, references, terms, conformance, notation, tiling types, tiling binding, implementation mechanism, and extension mechanism. It also includes four annexes that separate conformance testing, examples, the data dictionary, and mapping information.

Annex	What it covers
Annex A	Abstract test suite for conformance
Annex B	Tiling examples
Annex C	Data Dictionary for the UML model
Annex D	Mapping to other tiling models

What are the key requirements of ISO/DTS 19123-4?

ISO/DTS 19123-4 defines how a tiling schema is described, how it is bound to a coverage, and how implementations are tested. The practical value is that it gives a shared structure for tile boundaries, axes, origins, and metadata so software can exchange tiled coverage data consistently.

Tiling types and their use

Clause 6 separates aligned tiling from non-aligned tiling. Aligned tiling covers regular and irregular tiling, while non-aligned tiling in this document is only enumerated tiling. For implementers, this means the standard expects you to choose one of the supported patterns and represent it explicitly rather than inventing a new structure for each dataset.

Regular tiling is described with RegularAxis and equidistant span on each axis. Irregular tiling uses at least one IrregularAxis with ordered DirectPositions to express uneven spacing. In practice, that is the difference between a uniform grid and a grid that changes spacing along one axis.

Spatial reference and pixel-based descriptions

Clause 6 also requires that tiling in unit-less pixels be expressed only in index CRS and without georeference spacing. This matters for image-style data where the tile layout is counted in pixel indices rather than ground units.

Clause 9 allows tiling descriptions in other spatial reference systems, but the tiling properties must stay consistent with the tiling models in this document. That gives implementers room to extend the model while keeping origin, axis, geometry, and extent aligned with the core schema.

Tile shape and boundary rules

Clause 6 requires each hyperrectangular tile to use an ISO 19123-1 envelope to describe the tile shape. Clause 8 and Clause 9 then make the relationship between the tiling and the coverage explicit: the tiling boundary must match or contain the coverage envelope, and aligned tiling must place its origin in a corner of that envelope while accounting for padding.

That is important in practice because tile coordinates, coverage extents, and storage layout need to agree. If they do not, software may read the wrong pixels, clip data incorrectly, or misalign adjacent tiles.

Metadata and binding

Clause 7 requires a coverage that provides one or more tiling schemas to include those schemas as metadata components. Clause 8 says a coverage that provides tiling according to the UML diagram shall include at least one grid tiling description.

For readers, this means tiling is not just an internal storage detail. It has to be recorded in the coverage metadata so other systems can discover the tiling and use it for retrieval, processing, or exchange.

Conformance and testing

Clause 4 defines one conformance class for coverage tiling schema, and Annex A provides the abstract test suite. A claim of conformance is assessed against the relevant test cases in Annex A.

That makes the standard testable. In procurement, integration, or certification work, this gives a clear way to check whether a product or encoding really follows the tiling schema.

What terms does ISO/DTS 19123-4 define?

• aligned tiling schema - A tiling schema where tile spacing is arranged along each axis in alignment with the axes.
• irregular tiling schema - A tiling schema where at least one axis has irregular spacing.
• regular tiling schema - A tiling schema with equidistant spacing along each axis.
• non-aligned tiling schema - A tiling schema whose tile arrangement is not based on distances spaced along each axis.
• hyperrectangular tile - A hyperrectangular geometric tile with known properties, used here as the basic tile shape.
• tiled grid space - A space divided into smaller units or tiles according to a grid-based structure.
• CIS - Coverage Implementation Schema, used as an abbreviation in the document.
• CRS - Coordinate Reference System, the reference frame used for the tiling schema.

Who uses ISO/DTS 19123-4?

ISO/DTS 19123-4 is relevant to the geospatial community and to anyone defining or exchanging tiled coverage data. It is especially useful for developers of imagery, gridded data, and coverage encodings.

Typical users include:

• Geospatial software engineers designing tiling or chunking structures
• Data modelers defining coverage metadata and UML structures
• Quality managers checking conformance claims
• Buyers and integrators comparing coverage formats and exchange profiles
• Teams working with imagery and gridded data formats such as JPEG2000, GeoTIFF, NetCDF, and GMLJP2
• People extending coverage models to point clouds, meshes, or other gridded-space data

Which standards are used with ISO/DTS 19123-4?

ISO/DTS 19123-4 builds on several named standards and related parts:

• ISO 19103:2024 - provides the conceptual schema language and UML profile used in the document.
• ISO 19123-1:2023 - provides the fundamentals of coverages and the envelope-based concepts used throughout the tiling model.
• ISO/TS 19163-1:2016 - provides the content model for imagery and gridded data that the tiling schema is meant to bind to.
• ISO/TS 19163-2:2020 - provides the implementation schema for imagery and gridded data.
• ISO 19123-2 - is referenced in the introduction as the concrete implementation schema for coverages.
• ISO 19123-3 - is referenced in the introduction as the coverage processing language for extraction, filtering, processing, analytics, and fusion.
• ISO 19105 - is referenced in the introduction as the conformance and testing standard.
• ISO 19170-1 and EN ISO 19156 - are mentioned in the introduction as related geospatial standards.
• OGC 19-014r3 and OGC 17-083r4 - are used in Annex D for mapping regular tiling to other tiling models.

What does the ISO/DTS 19123-4 document contain?

ISO/DTS 19123-4 contains a UML-based model for tiling, with clauses that define aligned tiling, non-aligned tiling, binding, implementation, and extension mechanisms. The document also includes a set of abstract test cases in Annex A, so conformance can be checked in a repeatable way.

Annex B provides worked tiling examples for regular tiling, irregular tiling, and enumerated tiling. Annex C gives the data dictionary for the model classes and their attributes, including AbstractTiling, AlignedTiling, RegularTiling axis, IrregularTiling axis, Non-alignedTiling, and Hyperrectangular tile.

Annex D maps regular tiling to OGC 19-014r3 2D rectangular tiling and to OGC 17-083r4 2D tiling. That helps implementers relate this schema to other tiling frameworks used in practice.

FINAL DRAFT
Technical
Specification
ISO/TC 211
Geographic information — Schema
Secretariat: SIS
for coverage geometry and
Voting begins on:
functions —
2026-07-23
Part 4:
Voting terminates on:
2026-10-15
Tiling schema
Information géographique — Schéma de la géométrie et des
fonctions de couverture —
Partie 4: Schéma de tuilage
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/CEN PARALLEL PROCESSING LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
Reference number
FINAL DRAFT
Technical
Specification
ISO/TC 211
Geographic information — Schema
Secretariat: SIS
for coverage geometry and
Voting begins on:
functions —
Part 4:
Voting terminates on:
Tiling schema
Information géographique — Schéma de la géométrie et des
fonctions de couverture —
Partie 4: Schéma de tuilage
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
© ISO 2026
IN ADDITION TO THEIR EVALUATION AS
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/CEN PARALLEL PROCESSING
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
or ISO’s member body in the country of the requester.
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland Reference number
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
3.1 Terms and definitions .1
3.2 Abbreviated terms .3
4 Conformance . 3
5 Notation . 3
6 Tiling types . 3
6.1 Introduction .3
6.2 Aligned tiling .5
6.3 Non-aligned tiling .7
7 Tiling binding . 8
8 Implementation mechanism . 9
9 Extension mechanism .10
Annex A (normative) Abstract test suite .11
Annex B (informative) Tiling examples . 14
Annex C (normative) Data Dictionary .16
Annex D (informative) Tiling Mapping . 19
Bibliography .20

iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types
of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents). ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment,
as well as information about ISO's adherence to the World Trade Organization (WTO) principles in the
Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 211, Geographic information/Geomatics, in
collaboration with the European Committee for Standardization (CEN) Technical Committee CEN/TC 287,
Geographic Information, in accordance with the Agreement on technical cooperation between ISO and CEN
(Vienna Agreement).
A list of all parts in the ISO 19123 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
Introduction
Coverages are widely used in the geospatial community and related fields. Over the past two decades,
several related standards have been developed by the Geographic information/Geomatics committee, for
example the ISO 19123 series and the ISO 19163 series.
[1]
ISO 19123-1 defines at a high, implementation-independent level, the notion of coverages as digital
representations of space-time varying phenomena, corresponding to the notion of a field in physics.
[2] [3]
ISO 19123-2 specifies a concrete implementable, conformance-testableISO 19105 coverage structure
[4]
based on the abstract schema for coverages. ISO 19123-3 defines a coverage processing language for
server-side extraction, filtering, processing, analytics, and fusion of multi-dimensional geospatial coverages
representing, for example, spatio-temporal sensor, image, simulation, or statistics datacubes. ISO/TS 19163-1
[5]
specifies logical data structures and the rules for encoding the content components in the structures and
[6]
ISO/TS 19163-2 specifies implementation schema based on the content models for geographic imagery
[5] [7]
and gridded thematic data defined in the ISO/TS 19163-1 . However, the description for tiling , also
known as tessellation, is not included in these documents.
[8]
OGC 19-014r3 offers a fundamental basis for a conceptual tiling schema in 2D Euclidean space, which
[9]
could and should be extended to more dimensions. OGC 22-025r4 specifies tiling in 3D to handle massive
heterogeneous 3D geospatial datasets, such as photogrammetry, 3D buildings, and point clouds. OGC 17-
[10]
083r4 specifies a two dimensional Tile Matrix Set (TMS) and Tile Set Metadata(TSM), with focus on
storage and visualization, rather than online analysis. The extension support for describing 3D or higher
dimensions is informatively provided in its Annex J. However, the extension are mainly limited to regular
partitioning rules, and irregular axis cases require further exploration.
[11] [12]
ISO 19170-1 provides DGGS cells as data tiles and utilizes the concepts defined by EN ISO 19156 to
associate observations/spatial data to a DGGS cell. However, it is still not clear how detailed tiling schemas
for coverages can be mapped to the DGGS zones, especially the support for higher dimensions.
Without a concrete tiling schema, the specified UML defined in the ISO 19123 series and ISO 19163 series that
specifies coverage models cannot be mapped to the tiling/chunk encodings used in various data formats,
such as JPEG2000, GeoTIFF, NetCDF, GMLJP2, etc.
This document proposes a tiling schema for coverages as a binding between tiled grid space, and coverage
[1]
models based on ISO 19123-1 . Only tiling in multi-dimensional hyperrectangles are addressed in this
document, since rare data encoding formats support the partitioning in other shapes, such as hexagons,
Thiessen polygon, tetrahedron, icosahedron, dodecahedron, and et al.
The name and contact information of the maintenance agency for this document can be found at
www.iso.org/maintenance_agencies.

v
FINAL DRAFT Technical Specification ISO/DTS 19123-4:2026(en)
Geographic information — Schema for coverage geometry
and functions —
Part 4:
Tiling schema
1 Scope
This document specifies tiling schema that is suitable for binding tiled grid space and coverage models based
[1]
on ISO 19123-1 . Only tiling in multi-dimensional hyperrectangles are addressed in this document, since
rare data encoding formats support the partitioning in other shapes, such as hexagons, Thiessen polygon,
tetrahedron, icosahedron, dodecahedron, and et al.
2 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 19123-1:2023, Geographic information — Schema for coverage geometry and functions — Part 1:
Fundamentals
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 19123-1:2023 and the following
apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at http:// www .iso .org/ obp
3.1 Terms and definitions
3.1.1
aligned tiling schema
〈coverage tiling〉 schema where the partitioning of space into subspaces is structured such that the
arrangement of tiles is based on distances spaced in alignment along each axis
Note 1 to entry: In the context of a multi-dimensional coverage, unless otherwise specified in this document, the term
"aligned tiling" refers to a "aligned tiling schema".
3.1.2
irregular tiling schema
〈coverage tiling〉 schema where the partitioning of space into subspaces is structured such that the
arrangement of tiles is based on distances spaced along each axis, and, where at least one axis contains
irregular spacing
Note 1 to entry: In the context of a multi-dimensional coverage, unless otherwise specified in this document, the term
"irregular tiling" refers to a "irregular tiling schema".

3.1.3
hyperrectangular
geometric characteristic describing a shape that is the Cartesian product of intervals along each dimension
in a multi-dimensional coordinate system
Note 1 to entry: A hyperrectangular shape in n-dimensional space is defined by 2n boundaries, specifically the
minimum and maximum values along each axis, forming a convex polytope with faces perpendicular to the coordinate
axes.
Note 2 to entry: In two dimensions, a hyperrectangular shape is a rectangle; in three dimensions, it is a rectangular
prism or cuboid; in n dimensions, it generalizes to an n-orthotope.
3.1.4
hyperrectangular tile
〈coverage tiling〉 geometric shape as a hyperrectangular (3.1.3), with known properties, which can be, but
are not necessarily, the result of a tiling(tessellation)process
Note 1 to entry: In this document, an image is a special kind of grid. Regarding imagery and gridded data, range values
are assigned from the bounded pixels.
Note 2 to entry: In the context of multi-dimensional coverage, unless otherwise specified in this document, the term
"tile" refers to a "hyperrectangular tile".
3.1.5
hyperrectangular tiling schema
tiling schema, noun
〈coverage tiling〉 schema that describes how space is partitioned into multi-dimensional hyperrectangular
tile (3.1.4)
Note 1 to entry: In the context of a multi-dimensional coverage, unless otherwise specified in this document, the term
"tiling" refers to a "hyperrectangular tiling schema".
Note 2 to entry: A hyperrectangular tiling schema is a specific type of tiling schema (3.1.5) where the tiles are
hyperrectangular (3.1.3) in shape.
Note 3 to entry: When these subspaces are conterminous, a tiling is also called a tessellation as defined in
[13]
ISO 19123-1:2023 , 3.1.48.
3.1.6
non-aligned tiling schema
〈coverage tiling〉 schema where the partitioning of space into subspaces is structured such that the
arrangement of tiles is not based on distances spaced along each axis
Note 1 to entry: In the context of a multi-dimensional coverage, unless otherwise specified in this document, the term
"non-aligned tiling" refers to a "non-aligned tiling schema".
3.1.7
regular tiling schema
〈coverage tiling〉 schema where the partitioning of space into subspaces is structured such that the
arrangement of tiles is based equidistant spacing along each axis
Note 1 to entry: In the context of a multi-dimensional coverage, unless otherwise specified in this document, the term
"regular tiling" refers to a "regular tiling schema".
3.1.8
enumerated tiling schema
〈coverage tiling〉 schema where the partitioning of space is explicitly defined by a list of enumerated
hyperrectangular tiles (3.1.4)
Note 1 to entry: In the context of a multi-dimensional coverage, unless otherwise specified in this document, the term
"enumerated tiling" refers to an "enumerated tiling schema".

3.1.9
tiled space
〈coverage tiling〉 space that is partitioned into smaller, either regular or irregular shaped geometric units
called tiles
Note 1 to entry: Tiled space is the result of applying a tiling schema (3.1.5) to a space, creating a structured layout
where each tile represents a portion of the overall space.
3.1.10
tiled grid space
〈coverage tiling〉 space that is divided or partitioned into smaller units or tiles according to a grid-based
structure
3.2 Abbreviated terms
CIS Coverage Implementation Schema
CRS Coordinate Reference System
GML Geography Markup Language
GMLCOV GML Application Schema for Coverages
UML Unified Modeling Language
URI Unique Resource Identifier
4 Conformance
This document defines one conformance class, coverage tiling schema.
A specification, standard, test suite, or test tool claiming conformance to this document shall implement the
conformance class relevant to that specification target.
Conformance with this standard shall be assessed using all the relevant conformance test cases specified in
Annex A of this standard.
Requirements and conformance test URIs defined in this document are relative to http:// standards .isotc211
. or g / i s o19123 - 4/ -1/ 202 X .
5 Notation
Many diagrams that appear in this document are presented using the UML static structure diagram.
[14]
ISO 19103 Conceptual schema language presents the specific profile of UML used in the ISO 19100 family
of standards.
6 Tiling types
6.1 Introduction
A hierarchical category of tiling type is defined in Figure 1.
Tiling can be broadly categorized into two main types: aligned tiling and non-aligned tiling. Aligned tiling
includes regular tiling, where all axes are regular, meaning they have equidistant spacing throughout. This
uniform structure makes regular tiling highly efficient for data with consistent dimensions and predictable
patterns. In contrast, irregular tiling features at least one axis with irregular spacing, meaning the intervals
between tiles vary along that axis. This type of tiling is more flexible and can accommodate data with
varying dimensions or complex structures. Non-aligned tiling encompasses more complex strategies, such

as enumerated tiling, which involves explicitly defining tile positions and sizes, typically used for intricate
patterns or specific tile addressing. Additionally, there are other tiling methods that do not fit neatly into
these categories and are often custom-designed for unique data structures or applications. Understanding
these hierarchical categories helps in selecting the appropriate tiling strategy based on the specific
characteristics and requirements of the data being processed.
Figure 1 — Categories of coverage tiling schema
A package dependency diagram is defined in Figure 2. This document relies on the foundational concepts
[14] [5]
and structures defined in ISO 19103 and ISO/TS 19163-1 . Additionally, this document extends the
[1]
coverage models defined in ISO 19123-1 by providing a specific tiling schema that can be applied to
[2]
coverage implementation models as defined in ISO 19123-2 .
Figure 2 — Package dependency of coverage with tiling
Tiling structures are depicted in Figure 3.

[13]
NOTE The diagram utilizes several key types from ISO 19123-1:2023 , including DirectPositions, regularAxis,
and irregularAxis. These types serve as fundamental building blocks for defining aligned tiling schemas. Specifically,
[13]
regularAxis and irregularAxis are interfaces already defined in ISO 19123-1:2023 , representing axes with uniform
and non-uniform spacing, respectively. The regularAxis interface describes axes with equi-distant intervals, while
irregularAxis accommodates axes with varying intervals. Additionally, DirectPositions are used to specify exact
positions along irregular axes. The concept of padding is introduced to describe the space between the tiling boundary
and the coverage boundary when they do not overlap on a regularAxis, ensuring that the tiling schema accurately
reflects the spatial relationship between tiles and coverage data.
Figure 3 — Tiling structures
6.2 Aligned tiling
Aligned tiling can be regular and irregular tiling (Figure 3), depending on whether there is an axis containing
irregular spacing. Regular tiling employs an equi-distant spacing pattern along the width, while irregular
tiling can be varied on one axis, creating a more diverse spacing pattern. For clarity, refer to the examples
provided in Clause B.2 for regular tiling and Clause B.3 for irregular tiling. When applied to large-scale

coverage data, the description of the tiling can help to implement a cost-effective and time-efficient method
to identify and manage tiles of the desired region.
Requirement 1 /req/cts/AlignedTiling:
A aligned tiling shall be used to describe a tiling that has a structure based on distant spacing on each axis,
as described in Figure 3 and detailed in Clause C.3.
Requirement 2 /req/cts/RegularTilingAxis:
A Regular tiling shall be described in RegularAxis, with span as the equi-distant tiling spacing on each axis,
as described in Figure 3 and detailed in Clause C.4.
NOTE 1 The span here is the tile width along the axis.
Requirement 3 /req/cts/RegularAxisPadding:
A padding shall be used to describe space between tiling boundary and coverage boundary when both do
not overlap, as described in Figure 3 and detailed in Clause C.5.
EXAMPLE 1 A coverage description contains a tiling description expressed in Regular tiling (Figure 4).
Key
X, Y, T axes to determine 3-space
R1, R2, R3 span
O tiling origin
P1, P2, P3, P4 padding
L1, L2, L3 lower bound
Figure 4 — Regular tiling
Requirement 4 /req/cts/IrregularTiling:

A Irregular tiling shall contains at least one IrregularAxis, with ordered direct Positions specifying the
irregular spacing on the corresponding axis, as described in Figure 3 and detailed in Clause C.6.
EXAMPLE 2 A coverage description contains a tiling description expressed in Irregular tiling (Figure 5).
Key
X, Y, T axes to determine 3-space
R2 span
O tiling origin
P1, P2 padding
L1, L2, L3 lower bound
H1, H2, H3 upper bound
Figure 5 — Irregular tiling
Requirement 5 /req/cts/Unit-lessTiling:
When tiling in unit-less pixels, a tiling description shall be expressed with no georeference spacing, only in
index CRS as defined in ISO 19123-1:2023.
NOTE 2 A regular axis or irregular axis can have distant spacing in an ind
...

ISO/TC 211
Formatted: zzCover large
ISO/CD TSDTS 19123-4(en)
ISO/TC 211
Secretariat:  SIS
Date: 2026-07-09
Geographic information — Schema for coverage geometry and
functions —
Formatted: French (France)
Part 4:
Formatted: French (France)
Tiling schema
Formatted: French (France)
Information géographique — Schéma de la géométrie et des fonctions de couverture —
Partie 4: Schéma de tuilage
TTTTTTTTTTThhhhhhhhhhhiiiiiiiiiiis s s s s s s s s s s drdrdrdrdrdrdrdrdrdrdraaaaaaaaaaafffffffffffttttttttttt i i i i i i i i i i is s s s s s s s s s s sususususususususususubbbbbbbbbbbmmmmmmmmmmmiiiiiiiiiiitttttttttttttttttttttteeeeeeeeeeed d d d d d d d d d d tttttttttttooooooooooo      aaaaaaaaaaa      pppppppppppaaaaaaaaaaarrrrrrrrrrraaaaaaaaaaallellellellellellellellellellellel l l l l l l l l l l vvvvvvvvvvvooooooooooottttttttttteeeeeeeeeee i i i i i i i i i i innnnnnnnnnn      IIIIIIIIIIISSSSSSSSSSSOOOOOOOOOOO,,,,,,,,,,,      CCCCCCCCCCCEEEEEEEEEEEN.N.N.N.N.N.N.N.N.N.N.

ISO/CD TSDTS 19123-4:2026(en)
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication
Formatted: French (France)
may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying,
or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO
at the address below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: + 41 22 749 01 11
Formatted: French (France)
E-mail: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
ISO/CD TSDTS 19123-4:2026(en)
Contents
Foreword . iii
Introduction . iii
Scope . iii
Normative references . iii
Terms and definitions . iii
Terms and definitions . iii
Abbreviated terms . iii
Conformance . iii
Notation . iii
Tiling types . iii
Introduction . iii
Aligned tiling . iii
Non-aligned tiling . iii
Tiling binding . iii
Implementation mechanism . iii
Extension mechanism . iii
(normative) Abstract test suite . iii
(informative) Tiling examples. iii
(normative) Data Dictionary . iii
(informative) Tiling Mapping . iii
Bibliography . iii
Foreword . v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
3.1 Terms and definitions . 1
3.2 Abbreviated terms . 3
4 Conformance . 3
5 Notation . 4
6 Tiling types . 4
6.1 Introduction . 4
6.2 Aligned tiling . 7
6.3 Non-aligned tiling . 12
7 Tiling binding . 14
8 Implementation mechanism . 14
9 Extension mechanism . 16
Annex A (normative) Abstract test suite . 17
Annex B (informative) Tiling examples . 20
iii
ISO/CD TSDTS 19123-4:2026(en)
Annex C (normative) Data Dictionary . 23
Annex D (informative) Tiling Mapping . 26
Bibliography . 28

iv
ISO/CD TSDTS 19123-4:2026(en)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of
ISO documents should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawnISO draws attention to the possibility that some of the elementsimplementation of this
document may beinvolve the subject of use of (a) patent(s). ISO takes no position concerning the evidence,
validity or applicability of any claimed patent rights. ISO shall not be held responsible for identifying any or
all such patent rights. Details of any patent rights identified during the development in respect thereof. As of
the date of publication of this document will be in the Introduction and/or on the ISO list of patent declarations
, ISO had not received (seenotice of (a) patent(s) which may be required to implement this document.
However, implementers are cautioned that this may not represent the latest information, which may be
obtained from the patent database available at www.iso.org/patents). ISO shall not be held responsible for
identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as
well as information about ISO's adherence to the World Trade Organization (WTO) principles in the Technical
Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 211, Geographic information/Geomatics, in
collaboration with the European Committee for Standardization (CEN) Technical Committee CEN/TC 287,
Geographic Information, in accordance with the Agreement on technical cooperation between ISO and CEN
(Vienna Agreement).
A list of all parts in the ISO 19123 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
v
ISO/CD TSDTS 19123-4:2026(en)
Introduction
Coverages are widely used in the geospatial community and related fields. Over the past two decades, several
related standards have been developed by ISO/TC 211, e.g.the Geographic information/Geomatics committee,
for example the ISO 19123-x series and the ISO 19163-x standard series.
ISO 19123-1:2023ISO 19123-1 defines at a high, implementation-independent level, the notion of coverages
as digital representations of space-time varying phenomena, corresponding to the notion of a field in physics.
ISO 19123-2ISO 19123-2 specifies a concrete implementable, conformance-testableEN ISO 19105ISO 19105
coverage structure based on the abstract schema for coverages. ISO 19123-3ISO 19123-3 defines a coverage
processing language for server-side extraction, filtering, processing, analytics, and fusion of multi-dimensional
geospatial coverages representing, for example, spatio-temporal sensor, image, simulation, or statistics
datacubes. ISO/TS 19163-1:2016ISO/TS 19163-1 specifies logical data structures and the rules for encoding
the content components in the structures and ISO/TS 19163-2:2020ISO/TS 19163-2 specifies implementation
schema based on the content models for geographic imagery and gridded thematic data defined in the ISO/TS
[47]
19163-1:2016.ISO/TS 19163-1. However, the description for tiling , also known as tessellation, is not
Field Code Changed
included in these documents.
OGC 19-014r3OGC 19-014r3 offers a fundamental basis for a conceptual tiling schema in 2D Euclidean space,
which could and should be extended to more dimensions. OGC 22-025r4OGC 22-025r4 specifies tiling in 3D
to handle massive heterogeneous 3D geospatial datasets, such as photogrammetry, 3D buildings, and point
clouds. OGC 17-083r4OGC 17-083r4 specifies a two dimensional Tile Matrix Set (TMS) and Tile Set
Metadata(TSM), with focus on storage and visualization, rather than online analysis. The extension support
for describing 3D or higher dimensions is informatively provided in its Annex J. However, the extension are
mainly limited to regular partitioning rules, and irregular axis cases require further exploration.
ISO 19170-1ISO 19170-1 provides DGGS cells as data tiles and utilizes the concepts defined by ISO 19156EN
ISO 19156 to associate observations/spatial data to a DGGS cell. However, it is tillstill not clear how detailed
tiling schemas for coverages can be mapped to the DGGS zones, especially the support for higher dimensions.
Without a concrete tiling schema, the specified UML defined in the ISO 19123 series and ISO 19163 standard
series that specifies coverage models cannot be mapped to the tiling/chunk encodings used in various data
formats, such as JPEG2000, GeoTIFF, NetCDF, GMLJP2, and etc.
This document proposes a tiling schema for coverages as a binding between tiled grid space , and coverage
models based on ISO 19123-1:2023.ISO 19123-1. Only tiling in multi-dimensional hyperrectangles are
addressed in this document, since rare data encoding formats support the partitioning in other shapes, such
as hexagons, Thiessen polygon, tetrahedron, icosahedron, dodecahedron, and et al.
When a maintenance agency is involved, the following sentence shall be included to give a link to the page
where users can find details of the MA:
The name and contact information of the maintenance agency for this document can be found at
www.iso.org/maintenance_agencies.
vi
ISO/CD TSDTS 19123-4:2026(en)
Geographic information — Schema for coverage geometry and
functions —
Part 4:
Tiling schema
1 Scope
This document specifies tiling schema that is suitable for binding tiled grid space and coverage models based
on ISO 19123-1:2023.ISO 19123-1. Only tiling in multi-dimensional hyperrectangles are addressed in this
document, since rare data encoding formats support the partitioning in other shapes, such as hexagons,
Thiessen polygon, tetrahedron, icosahedron, dodecahedron, and et al.
2 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 19103:2024, Geographic information — Conceptual schema language
ISO 19123-1:2023, Geographic information — Schema for coverage geometry and functions — Part 1:
Fundamentals
ISO/TS 19163-1:2016, Geographic information — Content components and encoding rules for imagery and
gridded data — Part 1: Content model
ISO/TS 19163-2:2020, Geographic information — Content components and encoding rules for imagery and
gridded data — Part 2: Implementation schema
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 19123-1:2023 and the following
apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at http://www.iso.org/obp
3.1 Terms and definitions
3.1.1
aligned tiling schema
〈coverage tiling〉 schema where the partitioning of space into subspaces is structured such that the
arrangement of tiles is based on distances spaced in alignment along each axis
Note 1 to entry: In the context of a multi-dimensional coverage, unless otherwise specified in this document, the term
"aligned tiling" refers to a "aligned tiling schema".
ISO/CD TSDTS 19123-4:2026(en)
3.1.2
irregular tiling schema
〈coverage tiling〉 schema where the partitioning of space into subspaces is structured such that the
arrangement of tiles is based on distances spaced along each axis, and, where at least one axis contains
irregular spacing
Note 1 to entry: In the context of a multi-dimensional coverage, unless otherwise specified in this document, the term
"irregular tiling" refers to a "irregular tiling schema".
3.1.3
hyperrectangular
geometric characteristic describing a shape that is the Cartesian product of intervals along each dimension in
a multi-dimensional coordinate system
Note 1 to entry: A hyperrectangular shape in n-dimensional space is defined by 2n boundaries, specifically the minimum
and maximum values along each axis, forming a convex polytope with faces perpendicular to the coordinate axes.
Note 2 to entry: In two dimensions, a hyperrectangular shape is a rectangle; in three dimensions, it is a rectangular prism
or cuboid; in n dimensions, it generalizes to an n-orthotope.
3.1.4
hyperrectangular tile
〈coverage tiling〉 geometric shape as a hyperrectangular (3.1.3), with known properties, which can be, but are
not necessarily, the result of a tiling(tessellation)process
Note 1 to entry: In this document, an image is a special kind of grid. Regarding imagery and gridded data, range values
are assigned from the bounded pixels.
Note 2 to entry: In the context of multi-dimensional coverage, unless otherwise specified in this document, the term "tile"
refers to a "hyperrectangular tile".
3.1.5
hyperrectangular tiling schema
tiling schema, noun
〈coverage tiling〉 schema that describes how space is partitioned into multi-dimensional hyperrectangular tile
(3.1.4)
Note 1 to entry: In the context of a multi-dimensional coverage, unless otherwise specified in this document, the term
"tiling" refers to a "hyperrectangular tiling schema".
Note 2 to entry: A hyperrectangular tiling schema is a specific type of tiling schema (3.1.5) where the tiles are
hyperrectangular (3.1.3) in shape.
Note 3 to entry: When these subspaces are conterminous, a tiling is also called a tessellation as defined in ISO 19123-
[13]
1:2023, , 3.1.48.
3.1.6
non-aligned tiling schema
〈coverage tiling〉 schema where the partitioning of space into subspaces is structured such that the
arrangement of tiles is not based on distances spaced along each axis
Note 1 to entry: In the context of a multi-dimensional coverage, unless otherwise specified in this document, the term
"non-aligned tiling" refers to a "non-aligned tiling schema".
3.1.7
regular tiling schema
〈coverage tiling〉 schema where the partitioning of space into subspaces is structured such that the
arrangement of tiles is based equidistant spacing along each axis
ISO/CD TSDTS 19123-4:2026(en)
Note 1 to entry: In the context of a multi-dimensional coverage, unless otherwise specified in this document, the term
"regular tiling" refers to a "regular tiling schema".
3.1.8
enumerated tiling schema
〈coverage tiling〉 schema where the partitioning of space is explicitly defined by a list of enumerated
hyperrectangular tiles (3.1.4)
Note 1 to entry: In the context of a multi-dimensional coverage, unless otherwise specified in this document, the term
"enumerated tiling" refers to an "enumerated tiling schema".
3.1.9
tiled space
〈coverage tiling〉 space that is partitioned into smaller, either regular or irregular shaped geometric units
called tiles
Note 1 to entry: Tiled space is the result of applying a tiling schema (3.1.5) to a space, creating a structured layout where
each tile represents a portion of the overall space.
3.1.10
tiled grid space
〈coverage tiling〉 space that is divided or partitioned into smaller units or tiles according to a grid-based
structure
3.2 Abbreviated terms
CIS Coverage Implementation Schema
Formatted: Body Text
Formatted Table
CRS Coordinate Reference System
Formatted: Body Text
GML Geography Markup Language
Formatted: Body Text
GMLCOV GML Application Schema for Coverages
Formatted: Body Text
UML Unified Modeling Language
Formatted: Body Text
URI Unique Resource Identifier
Formatted: Body Text
4 Conformance
This document defines one conformance class:
— , coverage tiling schema.
Formatted: Body Text
A specification, standard, test suite, or test tool claiming conformance to this document shall implement the
conformance class relevant to that specification target.
Conformance with this standard shall be assessed using all the relevant conformance test cases specified in
Annex A of this standard.
Requirements and conformance test URIs defined in this document are relative to
http://standards.isotc211.org/iso19123-4/-1/202X.
ISO/CD TSDTS 19123-4:2026(en)
5 Notation
Many diagrams that appear in this document are presented using the Unified Modeling Language (UML) static
structure diagram. ISO 19103:2024ISO 19103 Conceptual schema language presents the specific profile of
UML used in the ISO 19100 family of standards.
6 Tiling types
6.1 Introduction
A hierarchical category of tiling type is defined in Figure 1.
Tiling can be broadly categorized into two main types: aligned tiling and non-aligned tiling . Aligned tiling
includes regular tiling , where all axes are regular, meaning they have equidistant spacing throughout. This
uniform structure makes regular tiling highly efficient for data with consistent dimensions and predictable
patterns. In contrast, irregular tiling features at least one axis with irregular spacing, meaning the intervals
between tiles vary along that axis. This type of tiling is more flexible and can accommodate data with varying
dimensions or complex structures. Non-aligned tiling encompasses more complex strategies, such as
enumerated tiling , which involves explicitly defining tile positions and sizes, typically used for intricate
patterns or specific tile addressing. Additionally, there are other tiling methods that do not fit neatly into these
categories and are often custom-designed for unique data structures or applications. Understanding these
hierarchical categories helps in selecting the appropriate tiling strategy based on the specific characteristics
and requirements of the data being processed.

Figure 1 — Categories of coverage tiling schema
A package dependency diagram is defined in Figure 2. This document relies on the foundational concepts and
structures defined in ISO 19103:2024 and ISO/TS 19163-1:2016. Additionally, this document extends the
coverage models defined in ISO 19123-1:2023ISO 19103 and ISO/TS 19163-1. Additionally, this document
extends the coverage models defined in ISO 19123-1 by providing a specific tiling schema that can be applied
to coverage implementation models as defined in ISO 19123-2ISO 19123-2.
ISO/CD TSDTS 19123-4:2026(en)
Figure 2 — Package dependency of coverage with tiling
Tiling structures are depicted in Figure 3.
ISO/CD TSDTS 19123-4:2026(en)
ISO/CD TSDTS 19123-4:2026(en)
NOTE The diagram utilizes several key types from ISO 19123-1:2023,ISO 19123-1:2023, including DirectPositions,
regularAxis, and irregularAxis. These types serve as fundamental building blocks for defining aligned tiling schemas.
Specifically, regularAxis and irregularAxis are interfaces already defined in ISO 19123-1:2023,ISO 19123-1:2023,
representing axes with uniform and non-uniform spacing, respectively. The regularAxis interface describes axes with
equi-distant intervals, while irregularAxis accommodates axes with varying intervals. Additionally, DirectPositions are
used to specify exact positions along irregular axes. The concept of padding is introduced to describe the space between
the tiling boundary and the coverage boundary when they do not overlap on a regularAxis, ensuring that the tiling schema
accurately reflects the spatial relationship between tiles and coverage data.
Figure 3 — Tiling structures
6.2 Aligned tiling
Aligned tiling can be regular and irregular tiling (Figure 3), depending on whether there is an axis containing
irregular spacing. Regular tiling employs an equi-distant spacing pattern along the width, while irregular tiling
can be varied on one axis, creating a more diverse spacing pattern. For clarity, refer to the examples provided
in Clause B.2 for regular tiling and Clause B.3 for irregular tiling . When applied to large-scale coverage data,
ISO/CD TSDTS 19123-4:2026(en)
the description of the tiling can help to implement a cost-effective and time-efficient method to identify and
manage tiles of the desired region.
Requirement 1 /req/cts/AlignedTiling:
A aligned tilin gtiling shall be used to describe a tiling that has a structure based on distant spacing on each
axis, as described in Figure 3 and detailed in Clause C.3.
Requirement 2 /req/cts/RegularTilingAxis:
A Regular tiling shall be described in RegularAxis, with span as the equi-distant tiling spacing on each axis, as
described in Figure 3 and detailed in Clause C.4.
NOTE 1 The span here is the tile width along the axis.
Requirement 3 /req/cts/RegularAxisPadding:
A padding shall be used to describe space between tiling boundary and coverage boundary when both do not
overlap, as described in Figure 3 and detailed in Clause C.5.
EXAMPLE 1 A coverage description contains a tiling description expressed in Regular tiling (Figure 4).
ISO/CD TSDTS 19123-4:2026(en)
Key
ISO/CD TSDTS 19123-4:2026(en)
X, Y, T axes to determine 3-space
R1, R2, R3 span
O tiling origin
P1, P2, P3, P4 padding
L1, L2, L3 lower bound
Figure 4 — Regular tiling
Requirement 4 /req/cts/IrregularTiling:
A Irregular tiling shall contains at least one IrregularAxis, with ordered direct Positions specifying the
irregular spacing on the corresponding axis, as described in Fi
...