FprEN ISO 19123-3

Geographic information - Schema for coverage geometry and functions - Part 3: Processing fundamentals (ISO/FDIS 19123-3:2023)

This document 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. Services implementing this language provide access to original or derived sets of coverage information, in forms that are useful for client-side consumption.
This document relies on the ISO 19123-1 abstract coverage model. In this edition, regular and irregular multi-dimensional grids are supported for axes that can carry spatial, temporal or any other semantics. Future editions will additionally support further axis types as well as further coverage types from ISO 19123-1, specifically, point clouds and meshes.

Geoinformation - Coverage Geometrie- und Funktionsschema - Teil 3: Grundlagen der Verarbeitung (ISO/FDIS 19123-3:2023)

Information géographique - Schéma de la géométrie et des fonctions de couverture - Partie 3: Principes de base du traitement (ISO/FDIS 19123-3:2023)

Le présent document définit un langage de traitement de couverture pour l'extraction, le filtrage, le traitement, l'analyse et la fusion côté serveur de couvertures géospatiales multidimensionnelles représentant, par exemple, des cubes de données spatio-temporelles de capteurs, d'images, de simulations ou de statistiques. Les services mettant en œuvre ce langage permettent d'accéder à des ensembles originaux ou dérivés d'informations de couverture, sous des formes utiles pour la consommation côté client.
Le présent document s'appuie sur le modèle de couverture abstrait de l'ISO 19123-1. Dans le présent document, les grilles multidimensionnelles régulières et irrégulières sont prises en charge pour des axes qui peuvent avoir une sémantique spatiale, temporelle ou autre. Les éditions suivantes incluront aussi d’autres types d’axes et d’autres types de couvertures provenant de l’ISO 19123-1, spécifiquement, les nuages de points et les maillages.

Geografske informacije - Shema za geometrijo podatkovnega sloja in funkcije - 3. del: Osnove obdelave (ISO/FDIS 19123-3:2023)

General Information

• Status: Not Published
• Publication Date: 18-Oct-2023
• ICS: 35.240.70 - IT applications in science
• Technical Committee: CEN/TC 287 - Geographic Information
• Drafting Committee: CEN/TC 287 - Geographic Information
• Current Stage: 6055 - CEN Ratification completed (DOR) - Publishing
• Start Date: 20-May-2023
• Due Date: 04-Jul-2024
• Completion Date: 20-May-2023
• Ref Project: kSIST FprEN ISO 19123-3:2023 - Geographic information - Schema for coverage geometry and functions - Part 3: Processing fundamentals (ISO/FDIS 19123-3:2023)

Standards Content (Sample)

SLOVENSKI STANDARD
oSIST prEN ISO 19123-3:2022
01-marec-2022
Geografske informacije - Shema za geometrijo podatkovnega sloja in funkcije - 3.
del: Osnove obdelave (ISO/DIS 19123-3:2022)
Geographic information - Schema for coverage geometry and functions - Part 3:
Processing fundamentals (ISO/DIS 19123-3:2022)

Geoinformation - Coverage Geometrie- und Funktionsschema - Teil 3: Grundlagen der

Verarbeitung (ISO/DIS 19123-3:2022)

Information géographique - Schéma de la géométrie et des fonctions de couverture -

Partie 3: Titre manque (ISO/DIS 19123-3:2022)
Ta slovenski standard je istoveten z: prEN ISO 19123-3
ICS:
07.040 Astronomija. Geodezija. Astronomy. Geodesy.
Geografija Geography
35.240.70 Uporabniške rešitve IT v IT applications in science
znanosti
oSIST prEN ISO 19123-3:2022 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN ISO 19123-3:2022
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oSIST prEN ISO 19123-3:2022
DRAFT INTERNATIONAL STANDARD
ISO/DIS 19123-3
ISO/TC 211 Secretariat: SIS
Voting begins on: Voting terminates on:
2021-12-16 2022-03-10
Geographic information — Schema for coverage geometry
and functions —
Part 3:
Processing fundamentals
ICS: 35.240.70
This document is circulated as received from the committee secretariat.
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
ISO/CEN PARALLEL PROCESSING
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 19123-3:2021(E)
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 SUPPORTING DOCUMENTATION. © ISO 2021
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oSIST prEN ISO 19123-3:2022
ISO 19123-3:####
ISO TC 211/WG 6
ISO/DIS 19123-3:2021(E)
Date: 2021-10-13
Geographic information — Schema for coverage geometry and
functions — Part 3: Processing Fundamentals
DIS stage
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication 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
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Phone: [phone]
Email: [e-mail]
Website: www.iso.org
© ISO 2021 – All rights reserved
Published in Switzerland
© ISO 2021 – All rights reserved
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oSIST prEN ISO 19123-3:2022
ISO/DIS 19123-3:2021(E)
Contents

Foreword ................................................................................................................................................................iv

Introduction ........................................................................................................................................................... v

1 Scope ................................................................................................................................................................. 1

2 Normative references ................................................................................................................................. 1

3 Terms, definitions, abbreviated terms and notation ...................................................................... 1

3.1 Terms and definitions ................................................................................................................................ 1

3.2 Abbreviated terms ....................................................................................................................................... 3

3.3 Notation ........................................................................................................................................................... 3

4 Conformance .................................................................................................................................................. 4

4.1 Interoperability and Conformance Testing ........................................................................................ 4

4.2 Organization .................................................................................................................................................. 4

5 Coverage model ............................................................................................................................................ 4

5.1 Overview ......................................................................................................................................................... 4

5.2 Coverage model ............................................................................................................................................ 4

5.3 Coverage Identifier ...................................................................................................................................... 5

5.4 Domain Set ..................................................................................................................................................... 5

5.5 Interpolation ................................................................................................................................................. 7

5.6 Range Values .................................................................................................................................................. 7

5.7 Range Type ..................................................................................................................................................... 8

5.8 Metadata .......................................................................................................................................................... 8

5.9 Coverage probing functionssynopsis .................................................................................................... 8

6 Coverage Processing Language ............................................................................................................... 9

6.1 Syntax and Semantics Definition Style .............................................................................................. 10

6.2 Coverage Processing Expressions ....................................................................................................... 10

6.3 Coverage-Generating Expressions ...................................................................................................... 14

6.4 Coverage Extraction Expressions ........................................................................................................ 18

6.5 Coverage Range-Value-Changing Expressions ............................................................................... 20

6.6 Coverage Derivation Expressions ....................................................................................................... 40

6.7 Coverage Aggregation Expressions .................................................................................................... 41

6.8 Coverage Encode/Decode Expressions ............................................................................................. 46

6.9 Expression evaluation ............................................................................................................................. 47

6.10 Evaluation response .......................................................................................................................... 49

Annex A (normative) Conformance Tests ............................................................................................... 50

Annex B (normative) ISO 19123-3 Expression Syntax ....................................................................... 51

Annex C (informative) Syntax Diagrams ................................................................................................. 58

Annex D (informative) Exemplary Service Descriptions ................................................................... 72

Bibliography ....................................................................................................................................................... 75

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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 drawn to the possibility that some of the elements of this document may be the subject of

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 of the document will be in the Introduction and/or on

the ISO list of patent declarations received (see www.iso.org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, 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

www.iso.org/iso/foreword.html.

This document was prepared by Technical Committee ISO/TC 211, Geographic information/Geomatics.

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 © ISO 2021 – All rights reserved
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Introduction

This standard defines, at a high, implementation-independent level, operations on coverages – i.e., digital

representations of space-time varying geographic phenomena – as defined in ISO 19123-1. Specifically,

regular and irregular grid coverages are addressed. The operations can be applied through an expression

language allowing composition of unlimited complexity and combining an unlimited number of coverages

for data fusion.
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oSIST prEN ISO 19123-3:2022
DRAFT INTERNATIONAL STANDARD ISO/DIS 19123-3:2021(E)
Geographic information — Schema for coverage geometry and
functions — Part 3: Processing Fundamentals
1 Scope

This document 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. Services implementing this language provide

access to original or derived sets of coverage information, in forms that are useful for client-side

consumption.

ISO 19123-3 relies on the abstract coverage model defined in ISO 19123-1. In this document, regular and

irregular multi-dimensional grids are supported, for axis that may carry spatial, temporal, or any other

semantics. Future versions may additionally support further axis types as well as point clouds and

meshes.

The language is functionally defined and free of any side effects has a solid conceptual foundation; only

two constructs establish all coverage processing:

A coverage constructor builds a coverage, either from scratch or by deriving it from one or more other

coverages.

The ISO 19123-3 language is independent from any particular request and response encoding, as no

concrete request/response protocol is assumed. Hence, this standard does not define a service, but acts

as the foundation for defining service standards functionality. One such target framework is OGC Web

[3].
Coverage Service (WCS)

In its current version ISO 19123-3 supports ISO 19123-1 grid coverages with index, regular, and irregular

axes. In the future it is foreseen that the standard gets extended so as to address all coverage types of

ISO 19123-1.
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 19123-1:2021, Geographic information — Coverage Fundamentals
3 Terms, definitions, abbreviated terms and notation
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminology databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at https://www.electropedia.org/
3.1.1
axis

〈coordinate geometry〉 linear feature from which a one-dimensional coordinate system is constructed

Note 1 to entry: This definition is established in accordance with ISO 19111:2019, Clause 10.4.

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[SOURCE: ISO 19123-1:2021, 3.1.2]
3.1.2
coordinate
one of a sequence of numbers designating the position of a point

Note 1 to entry: A direct position is described by an ordered sequence of coordinates. The number of elements in a

direct position is established by the number of axes of the coverage.
[SOURCE: ISO 19123-1:2021, 3.1.2]
3.1.3
coordinate reference system
coordinate system that is related to an object by a datum

Note 1 to entry: Geodetic and vertical datums are referred to as reference frames.

Note 2 to entry: For geodetic and vertical reference frames, the object will be the Earth. In planetary applications,

geodetic and vertical reference frames may be applied to other celestial bodies.
[SOURCE: ISO 19111:2019, 3.1.9]
3.1.4
coverage

feature that acts as a function to return values from its range for any direct position within its domain

[SOURCE: ISO 19123-1:2021, 3.1.8]
3.1.5
coverage CRS
the common CRS in which all coordinates of a coverage are expressed

Note 1 to entry: Sometimes a coverage’s CRS is also referred to as the coverage’s native CRS.

[SOURCE: ISO 19123-1:2021, 3.1.9]
3.1.6
(coverage) dimension
coordinate dimension

number of separate decisions needed to describe a position in a coordinate

system

Note 1 to entry: This is equivalent to “the number of axes in the coordinate reference system of the coverage domain

set”.
[SOURCE: ISO 19123-1:2021, 3.1.10]
3.1.7
direct position

position described by a single set of coordinates within a coordinate reference

system

Note 1 to entry: Cells in a grid coverage are identified by their direct position in the domain set of this coverage.

[SOURCE: ISO 19123-1:2021, 3.1.13]
3.1.8
domain
well-defined set
Note 1 to entry: All elements within a domain (set) are of a given type.
[SOURCE: ISO 19123-1:2021, 3.1.16]
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3.1.9
evaluation

determination of the values of a coverage at a direct position within the domain of the

coverage
[SOURCE: ISO 19123-1:2021, 3.1.18]
3.1.10
grid

nonempty, ordered set of axes with a set of positions along each axis acting as reference

points for connected compact smooth hypersurfaces

Note 1 to entry: In ISO 19123:2005, a grid consists of a network composed of one or more sets of curves in which

the members of each set intersect the members of the other sets. This definition is intended to be applicable also to

the 1-D case.

Note 2 to entry: The ISO 19123:2005 definition is equivalent to the revised definition of this document.

[SOURCE: ISO 19123-1:2021, 3.1.28]
3.1.11
grid coordinate reference system

coordinate reference system for the positions in a grid that uses a defined coordinate system congruent

with the coordinate system described by the GridEnvelope and axisLabels of gml:GridType

Note 1 to entry: The grid’s CRS is identical to the CRS of the coverage defined by that grid.

[SOURCE: ISO 19123-1:2021, 3.1.29]
3.1.12
grid coordinates

sequence of two or more numbers specifying a position with respect to its location on a grid

[SOURCE: ISO 19115-2:2019, 3.15]
3.1.13
index coordinate reference system
Index CRS
multi-dimensional non-georeferenced Cartesian grid coordinates reference system
[SOURCE: ISO 19115-2:2019, 3.1.39]
3.1.14
(coverage) probing function
function extracting information from the coverage
3.1.15
range

set of feature attribute values associated by a function, the coverage, with the elements of the

domain of a coverage

Note 1 to entry: This is consistent with the more generic definition of range in ISO 19107:2019.

[SOURCE: ISO 19123-1:2021, 3.1.47]
3.2 Abbreviated terms
CRS Coordinate Reference System
3.3 Notation

Table 1 lists the other standards and packages in which UML classes used in this document have been

defined.
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Table 1 — Sources of externally defined UML classes
Prefix International Standard Package
CV ISO 19123-1 Coverage Core
4 Conformance
4.1 Interoperability and Conformance Testing

This document being an abstract standard allows for multiple different implementations and does not

define a standardized interoperable implementation. Hence, standardization target primarily are

specifications of coverage operations and services which may use this language to describe the semantics

of their operations.

Conformance testing is accomplished by validating a candidate concretization against all requirements

by exercising the tests set out in Annex A.
4.2 Organization
Table 2 — Conformance classes
Conformance class Clause Identifying URL

Coverage Processing 6 https://standards.isotc211.org/19123/-3/1/conf/coverage-processing

5 Coverage model
5.1 Overview

This standard defines a language whose expressions accept any number of input coverages (together

with further common inputs like numbers) to generate any number of output coverages. Coverages are

defined in ISO 19123-1.
5.2 Coverage model

For the reader’s convenience a brief informal (and non-normative) recapitulation is given. Following the

mathematical notion of a function that maps elements of a domain (here: spatio-temporal coordinates)

to a range (here: “pixel”, “voxel”, etc. values), a coverage consists of (Figure 1):

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a) an identifier which uniquely identifies a coverage in some context (here: the context of an expression)

b) a domain set of coordinate points (expressed in a common Coordiante Reference System, CRS): “where

in the multi-dimensional space can I find values?”

c) a probing function which answers for each coverage coordinate in the domain set (“direct position”):

“what is the value here?”
d) a range type: “what do those values mean?”
e) optional metadata: “what else should I know about these data?”
Figure 1 — CV_Coverage and CV_GeneralGridCoverage with CV_Grid (ISO 19123-1)

NOTE CV_Coverage in ISO 19123-1 defines an interface which describes such an object’s behavior, but does not

yet assume any particular data structure.

Below a brief recapitulation of ISO 19123-1 grid coverages is given; at the same time, probing functions

are introducedwhich extracts components from some given coverage. These probing functions are

defined as part of the ISO 19123-1 interface class definition. They serve to define this standard’s language

semantics in Clause 6.
5.3 Coverage Identifier

Coverages have an identifier which is used in a ISO 19123-3 query to address a coverage. Therefore, this

identifier must be unique within some context (here: an ISO 19123-3 query).

NOTE In a concrete service, coverages available typically would be those which are stored on this server, where

access control allows addressing the coverage according to the user sending the request, etc. All these aspects are

out of scope of this standard.
The corresponding ISO 19123-1 probing function for a coverage C is:
id( C )

Frequently new coverages are created in a query; initially, they do not carry any identifier, rather their id

value is the empty string.
5.4 Domain Set

The domain set contains the coordinate tuples describing the coverage’s direct positions, which for the

purpose of this standard all sit on a multi-dimensional grid. Informally speaking this means that every

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direct position inside the grid has exactly one next neighbor in both directions of every axis, except for

the rim where obviously less neighbours are available. Figure 2 shows some regular and irregular grid

examples.
Figure 2 — Sample regular and irregular grid structures (ISO 19123-1)

The grid description depends on the complexity of the grid. As a grid is composed from an ordered

sequence of axes the resulting complexity is determined by the types of axes (such as integer versus Lat

versus time) as well as the rules determining the direct positions along these axes. The following axis

types defined in ISO 19123-1 are supported by ISO 19123-3:

— A Cartesian (“index”) axis just requires lower and upper bound (which are of type integer).

— A regular axis which can be described by lower and upper bounds together with a constant distance,

the resolution.

— An irregular axis which has individual distances, described by a sequence of coordinates.

NOTE 1 As explained in ISO 19123-1, the specialized grid types of superseded ISO 19123:2005 can be modeled

through the ISO 19123-1 GeneralGridCoverage concept: a RectifiedGrid is a grid where all axes are of type Cartesian

or regular; a ReferenceableGrid is a grid where at least one axis is not of these types.

As per ISO 19123-1, the coverage domain set with its axes has a single native CRS which may allow

georeferencing. Additionally, the underlying grid structure is defined through aCartesian grid CRS. Both

CRSs have the same dimension, i.e.: number of axes. CRSs are addressed by name in ISO 19123-3

expressions. Both ISO 19123-1 and ISO 19123-3 do not make any assumptions about the nature of

identifying CRSs, but rather treat them as opaque strings.

The native CRS of a domain set is obtained through function crs(C), its grid CRS through function

gridCrs(C).
nativeCrs(C)
gridCrs(C)

The particular definition of CRSs and axes is out of the scope of this standard, rather this is defined in

ISO 19111. That said, this standard assumes an auxiliary probing function axisList() which extracts the

ordered list of axes (a ,…,a ) from such a d-dimensional CRS:
1 d
axisList( crs )

NOTE 2 This function can be applied to both native and grid CRSs, so only one such function is necessary.

Each axis contributes coordinates from some nonempty, totally ordered set of values which can be

numeric or, in the general case, strings (such as “2020-08-05T”).

For some given coverage C, two probing functions deliver the domain setof a coverage in its native CRS

and in its Cartesian grid CRS, respectively:
domainSet( C )
gridDomainSet( C )
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The contents of the domain information describes the coverage’s extent:

a) for each axis the lower and upper bound of the Direct Positions are listed in axis order

b) per axis, the following information is available:
1) for index axes: nothing further;
2) for regular axes: the resolution;
3) for irregular axes: the sequence of points.

The contents of the grid information usually is simpler than the native domain because the underlying

CRS is always index-only. Consequently, it consists of a list of lower bound / upper bound pairs, one per

axis.

This information is accessible through overloaded versions of the abovementioned functions. For some

coverage C that has an axis a, the following expressions return lower and upper bound, respectively:

domainSet( C, a).lo
domainSet( C, a).hi
gridDomainSet( C, a ).lo
gridDomainSet( C, a ).hi
5.5 Interpolation

In ISO 19123-1 a coverage contains admissible interpolation information, characterized individually per

axis.

NOTE 1 As per ISO 19123-1 every coverage has one interpolation method associated per axis. In practice, coverages

may allow several interpolation methods to be picked by the user. Conceptually, however, two coverages differing

only in the interpolation methods are distinct as they will deliver identical range values on their direct positions,

but differing values in between those. On the abstract level of ISO 19123-1 this ambiguity is not desirable.

For the purpose of this standard a special interpolation method none is assumed in addition to those

defined, e.g., in ISO 19123-1, Annex B. None indicates that no interpolation is possible along the axis

under consideration.

NOTE 2 Interpolation method none is different from nearest-neighbor: An interpolation of nearest-neighbor

provides values inbetween Direct Positions which are derived from the closest Direct Position. Interpolation none

means that no values are provided between Direct Positions, in other words: the evaluation function is undefined

on any non-Direct Position.

Function interpolation(C,a) returns the list of interpolation methods applicable on each axis of coverage

C, in order of the axis sequence. For dimension(C)=d the probing function delivers interpolation method

list(m ,…,m ):
1 d
interpolation(C)

This function is overloaded to extract the interpolation method associated with axis a of C:

interpolation(C,a)

NOTE 3 Interpolation is particularly relevant with functions scale() and project().

5.6 Range Values

The range value at some direct positionpcan be obtained with function evaluate (p) which, for some

given coverage C, returns the value associated with p∈domainSet(C) expressed in the coverage’s native

CRS. Simultaneously, function evaluateGrid (p) does the same for some p∈gridDomainSet(C) expressed

in the coverage’s grid CRS. The mechanics of a coverage, as per ISO 19123-1, ensures coherence between

native and (Cartesian) grid coordinates.
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The corresponding probing function integrates native CRS and grid CRS based access as per ISO 19123-1:

value(C,p) := evaluateC(p) for some location p∈domainSet(C)
value(C,p) := evaluateGridC(p) for some location p∈gridDomainSe(C)

Interpolation guides whether the value () function is defined on coordinates outside the Direct Position

set, and how this value is determined from the values available at the Direct Positions.

5.7 Range Type

A coverage’s range type description can be obtained through probing function rangeType() which delivers

a set of tuples containing at least field names and field type:
rangeType(C)

Again, this function gets overloaded to obtain the coverage range type of some particular range field

component f:
rangeType(C, f)

For the purpose of this standard only the common programming language data types are considered, and

only on a high, abstract level: Boolean, integer, float, complex, as well as records over those are assumed

to be available.

NOTE The concrete range types available in coverage processing are determined by concretizations of

ISO 19123-3. Typically, the standard programming language data types will be available, such as (unsigned) short,

int, and long
...