Geographic information - Linear referencing (ISO 19148:2021)

This document specifies a conceptual schema for locations relative to a one-dimensional object as
measurement along (and optionally offset from) that object. It defines a description of the data and
operations required to use and support linear referencing.
This document is applicable to transportation, utilities, environmental protection, location-based
services and other applications which define locations relative to linear objects. For ease of reading,
most examples discussed in this document come from the transportation domain.

Geoinformation - Lineares Bezugssystem (ISO 19148:2021)

Information géographique - Référencement linéaire (ISO 19148:2021)

Geografske informacije - Linearno georeferenciranje (ISO 19148:2021)

General Information

Status
Published
Public Enquiry End Date
13-Sep-2020
Publication Date
25-May-2021
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
18-May-2021
Due Date
23-Jul-2021
Completion Date
26-May-2021

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SLOVENSKI STANDARD
SIST EN ISO 19148:2021
01-julij-2021
Nadomešča:
SIST EN ISO 19148:2012
Geografske informacije - Linearno georeferenciranje (ISO 19148:2021)
Geographic information - Linear referencing (ISO 19148:2021)
Geoinformation - Lineares Bezugssystem (ISO 19148:2021)
Information géographique - Référencement linéaire (ISO 19148:2021)
Ta slovenski standard je istoveten z: EN ISO 19148:2021
ICS:
07.040 Astronomija. Geodezija. Astronomy. Geodesy.
Geografija Geography
35.240.70 Uporabniške rešitve IT v IT applications in science
znanosti
SIST EN ISO 19148:2021 en,fr,de

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

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SIST EN ISO 19148:2021
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SIST EN ISO 19148:2021
EN ISO 19148
EUROPEAN STANDARD
NORME EUROPÉENNE
April 2021
EUROPÄISCHE NORM
ICS 35.240.70 Supersedes EN ISO 19148:2012
English Version
Geographic information - Linear referencing (ISO
19148:2021)

Information géographique - Référencement linéaire Geoinformation - Lineares Bezugssystem (ISO

(ISO 19148:2021) 19148:2021)
This European Standard was approved by CEN on 10 March 2021.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this

European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references

concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN

member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by

translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management

Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and

United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 19148:2021 E

worldwide for CEN national Members.
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SIST EN ISO 19148:2021
EN ISO 19148:2021 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

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SIST EN ISO 19148:2021
EN ISO 19148:2021 (E)
European foreword

This document (EN ISO 19148:2021) has been prepared by Technical Committee ISO/TC 211

"Geographic information/Geomatics" in collaboration with Technical Committee CEN/TC 287

“Geographic Information” the secretariat of which is held by BSI.

This European Standard shall be given the status of a national standard, either by publication of an

identical text or by endorsement, at the latest by October 2021, and conflicting national standards shall

be withdrawn at the latest by October 2021.

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

patent rights. CEN shall not be held responsible for identifying any or all such patent rights.

This document supersedes EN ISO 19148:2012.

According to the CEN-CENELEC Internal Regulations, the national standards organizations of the

following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,

Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,

Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of

North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the

United Kingdom.
Endorsement notice

The text of ISO 19148:2021 has been approved by CEN as EN ISO 19148:2021 without any modification.

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SIST EN ISO 19148:2021
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SIST EN ISO 19148:2021
INTERNATIONAL ISO
STANDARD 19148
Second edition
2021-04
Geographic information — Linear
referencing
Information géographique — Référencement linéaire
Reference number
ISO 19148:2021(E)
ISO 2021
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SIST EN ISO 19148:2021
ISO 19148:2021(E)
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
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
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SIST EN ISO 19148:2021
ISO 19148:2021(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction ..............................................................................................................................................................................................................................vii

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

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

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Abbreviated terms and UML notation ............................................................................................................................................ 5

4.1 Abbreviated terms ............................................................................................................................................................................... 5

4.2 UML notation ............................................................................................................................................................................................ 5

5 Conformance ............................................................................................................................................................................................................. 5

5.1 Conformance overview .................................................................................................................................................................... 5

5.2 Conformance classes .......................................................................................................................................................................... 6

5.2.1 General...................................................................................................................................................................................... 6

5.2.2 Data type conformance .............................................................................................................................................. 6

5.2.3 Operation conformance ............................................................................................................................................. 6

6 Linear referencing .............................................................................................................................................................................................. 7

6.1 Background ................................................................................................................................................................................................ 7

6.1.1 Linear referencing concepts .................................................................................................................................. 7

6.1.2 Linear referencing packages ...............................................................................................................................17

6.2 Package: Linear Referencing System .................................................................................................................................18

6.2.1 Semantics ............................................................................................................................................................................18

6.2.2 PositionExpression .....................................................................................................................................................19

6.2.3 LinearElement ...................................................................... ...........................................................................................20

6.2.4 LinearElementType ....................................................................................................................................................21

6.2.5 ILinearElement ...............................................................................................................................................................21

6.2.6 IFeature .................................................................................................................................................................................22

6.2.7 ISpatial ...................................................................................................................................................................................23

6.2.8 LinearReferencingMethod ....................................................................................................................................24

6.2.9 DistanceAlongDirection ..........................................................................................................................................25

6.2.10 LRMType ..............................................................................................................................................................................25

6.2.11 DistanceExpression ....................................................................................................................................................26

6.2.12 Referent ................................................................................................................................................................................27

6.2.13 ReferentType ....................................................................................................................................................................28

6.2.14 ValueExpression ............................................................................................................................................................29

6.3 Package: Linear Referencing Towards Referent ......................................................................................................30

6.3.1 Semantics ............................................................................................................................................................................30

6.3.2 LRMWithTowardsReferent ..................................................................................................................................30

6.3.3 DistanceExpression ....................................................................................................................................................31

6.4 Package: Linear Referencing Offset ....................................................................................................................................31

6.4.1 Semantics ............................................................................................................................................................................31

6.4.2 LRMWithOffset ...............................................................................................................................................................33

6.4.3 LateralOffsetDirection ..............................................................................................................................................34

6.4.4 VerticalOffsetDirection ............................................................................................................................................34

6.4.5 LateralOffsetDistanceExpression ...................................................................................................................34

6.4.6 LateralOffsetExpression .........................................................................................................................................35

6.4.7 LateralOffsetReferent ........................................................................................................................................... .....36

6.4.8 VerticalOffsetExpression ........................................................................................................................................37

6.4.9 VerticalOffsetReferent ..............................................................................................................................................38

6.4.10 ICrossSectionalConvention ..................................................................................................................................38

6.4.11 ICrossSectionalConventionPart .......................................................................................................................39

6.5 Package: Linear Referencing Offset Vector ..................................................................................................................40

6.5.1 Semantics ............................................................................................................................................................................40

6.5.2 VectorOffsetDistanceExpression .....................................................................................................................40

© ISO 2021 – All rights reserved iii
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SIST EN ISO 19148:2021
ISO 19148:2021(E)

6.5.3 VectorOffsetExpression ...........................................................................................................................................41

6.6 Package: Linearly Located Event ..........................................................................................................................................42

6.6.1 Semantics ............................................................................................................................................................................42

6.6.2 Linearly located event ..............................................................................................................................................43

6.6.3 Event ........................................................................................................................................................................................44

6.6.4 AttributeEvent.................................................................................................................................................................45

6.6.5 FeatureEvent ....................................................................................................................................................................46

6.6.6 EventLocation ..................................................................................................................................................................47

6.6.7 AtLocation ..........................................................................................................................................................................47

6.6.8 FromToLocation ............................................................................................................................................................47

6.6.9 EventTime ...........................................................................................................................................................................48

6.6.10 EventInstant ......................................................................................................................................................................49

6.6.11 EventPeriod .......................................................................................................................................................................49

6.7 Package: Linear Segmentation ...............................................................................................................................................49

6.7.1 Semantics ............................................................................................................................................................................49

6.7.2 SegmentableFeature ..................................................................................................................................................50

6.7.3 LinearSegmentSet ........................................................................................................................................................51

6.7.4 LinearSegment ................................................................................................................................................................52

Annex A (normative) Abstract test suite .......................................................................................................................................................54

Annex B (informative) Generalized Model for Linear Referencing ...................................................................................58

Annex C (informative) Commonly used linear referencing methods and models .............................................61

Annex D (informative) Application Schema example ......................................................................................................................84

Annex E (informative) Event and segmentation examples .........................................................................................................87

Annex F (informative) Backwards compatibility with ISO 19148:2012 .......................................................................96

Bibliography .............................................................................................................................................................................................................................98

iv © ISO 2021 – All rights reserved
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SIST EN ISO 19148:2021
ISO 19148:2021(E)
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,

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).

This second edition cancels and replaces the first edition (ISO 19148:2012), which has been technically

revised.
The main changes compared to the previous edition are as follows:

— revision of the definition of the term linear element, removing a circular reference with the definition

for the term linear referencing;
— introduction of the definition of the term referent;

— revision of the conceptual schema to meet current standards and harmonize with other ISO/TC 211

International Standards;

— refactoring of the core Linear Referencing System package, abstracting implementation classes into

a new Application Schema package which is now presented as an example in Annex D;

— introduction of an approach addressing broken-chainage;
— introduction of an enumeration addressing directionality of measurements;

— introduction of an approach addressing Cross-Sectional Positioning (XSP) conventions;

— introduction of an approach addressing Measures with Uneven Distribution;

— refactoring of the Linearly Located Event package dropping the previous assumption that the Linear

Element was always of a Feature type;
— introduction of simplifications of the conceptual schema;
© ISO 2021 – All rights reserved v
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SIST EN ISO 19148:2021
ISO 19148:2021(E)
— additional example illustrating Measures with Uneven Distribution in Annex C;

— introduction of information about some standards implementing the conceptual schema described

in this document in Annex C;

— additional example illustrating Secondary Linear Referencing Systems in Annex E;

— the correction of minor errors;

— introduction of a detailed overview regarding changes and backwards compatibility in Annex F.

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.
vi © ISO 2021 – All rights reserved
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SIST EN ISO 19148:2021
ISO 19148:2021(E)
Introduction

This document is a description of the data and operations required to support linear referencing. This

includes Linear Referencing Systems, linearly located events and linear segments.

Linear Referencing Systems enable the specification of positions along linear objects. The approach is

[12]

based upon the Generalized Model for Linear Referencing first standardized within ISO 19133:2005.

This document extends that which was included in ISO 19133, both in functionality and explanation.

ISO 19109 supports features representing discrete objects with attributes with values which apply to

the entire feature. ISO 19123 allows the attribute value to vary, depending upon the location within a

feature, but does not support the assignment of attribute values to a single point or length along a linear

feature. Linearly located events provide the mechanism for specifying attribution of linear objects

when the attribute value varies along the length of a linear feature. A Linear Referencing System is used

to specify where along the linear object each attribute value applies. The same mechanism can be used

to specify where along a linear object another object is located, such as guardrail or a traffic accident.

It is common practice to segment a linear object with linearly located events, based upon one or

more of its attributes. The resultant linear segments are attributed with just the attributes used in

the segmentation process, ensuring that the linear segments are homogeneous in value for these

segmenting attributes.

In accordance with the ISO/IEC Directives, Part 2, 2018, Rules for the structure and drafting of

International Standards, in International Standards the decimal sign is a comma on the line. However,

the General Conference on Weights and Measures (Conférence Générale des Poids et Mesures) at its

meeting in 2003 passed unanimously the following resolution:

“The decimal marker shall be either a point on the line or a comma on the line.” In practice, the choice

between these alternatives depends on customary use in the language concerned. In the technical areas

of geodesy and geographic information it is customary for the decimal point always to be used, for all

languages. That practice is used throughout this document.
© ISO 2021 – All rights reserved vii
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SIST EN ISO 19148:2021
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SIST EN ISO 19148:2021
INTERNATIONAL STANDARD ISO 19148:2021(E)
Geographic information — Linear referencing
1 Scope

This document specifies a conceptual schema for locations relative to a one-dimensional object as

measurement along (and optionally offset from) that object. It defines a description of the data and

operations required to use and support linear referencing.

This document is applicable to transportation, utilities, environmental protection, location-based

services and other applications which define locations relative to linear objects. For ease of reading,

most examples discussed in this document come from the transportation domain.
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, Geographic information — Conceptual schema language
ISO 19107, Geographic information — Spatial schema
ISO 19108, Geographic information — Temporal schema
ISO 19111, Geographic information — Referencing by coordinates
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

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

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
attribute event

value of an attribute of a feature (3.4) that can apply to only part of the feature

Note 1 to entry: An attribute event includes the linearly referenced location (3.16) where the attribute value

applies along the attributed feature (3.2).

Note 2 to entry: An attribute event can be qualified by the instant (3.8) in which, or period (3.20) during which,

the attribute value applied.
3.2
attributed feature
feature (3.4) along which an attribute event (3.1) applies
3.3
direct position

position (3.21) described by a single set of coordinates within a coordinate reference system

[SOURCE: ISO 19136-1:2020, 3.1.20]
© ISO 2021 – All rights reserved 1
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SIST EN ISO 19148:2021
ISO 19148:2021(E)
3.4
feature
abstraction of real-world phenomena
[SOURCE: ISO 19101-1:2014, 4.1.11]
3.5
feature event

information about the occurrence of a located feature (3.17) along a locating feature (3.18)

Note 1 to entry: A feature event includes the linearly referenced location (3.16) of the located feature along the

locating feature.

Note 2 to entry: A feature event can be qualified by the instant (3.8) in which, or period (3.20) during which, the

feature event occurred.
3.6
geometric primitive

geometric object representing a single, connected, homogeneous (isotropic) element of space

Note 1 to entry: Geometric primitives are non-decomposed objects that present information about geometric

configuration. They include points, curves, surfaces and solids. Many geometric objects behave

...

SLOVENSKI STANDARD
oSIST prEN ISO 19148:2020
01-september-2020
Geografske informacije - Linearno georeferenciranje (ISO/DIS 19148:2020)
Geographic information - Linear referencing (ISO/DIS 19148:2020)
Geoinformation - Lineares Bezugssystem (ISO/DIS 19148:2020)
Information géographique - Référencement linéaire (ISO/DIS 19148:2020)
Ta slovenski standard je istoveten z: prEN ISO 19148
ICS:
07.040 Astronomija. Geodezija. Astronomy. Geodesy.
Geografija Geography
35.240.70 Uporabniške rešitve IT v IT applications in science
znanosti
oSIST prEN ISO 19148:2020 en,fr,de

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

---------------------- Page: 1 ----------------------
oSIST prEN ISO 19148:2020
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oSIST prEN ISO 19148:2020
DRAFT INTERNATIONAL STANDARD
ISO/DIS 19148
ISO/TC 211 Secretariat: SIS
Voting begins on: Voting terminates on:
2020-06-30 2020-09-22
Geographic information — Linear referencing
Information géographique — Référencement linéaire
ICS: 35.240.70
THIS DOCUMENT IS A DRAFT CIRCULATED
This document is circulated as received from the committee secretariat.
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
ISO/CEN PARALLEL PROCESSING
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 19148:2020(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 2020
---------------------- Page: 3 ----------------------
oSIST prEN ISO 19148:2020
ISO/DIS 19148:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020

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
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
---------------------- Page: 4 ----------------------
oSIST prEN ISO 19148:2020
ISO/DIS 19148:2020(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction ................................................................................................................................................................................................................................vi

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

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

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Symbols, abbreviated terms, backwards compatibility, and UML notation ............................................4

4.1 Symbols and abbreviated terms............................................................................................................................................... 4

4.2 Backwards compatibility ......... ....................................................................................................................................................... 5

4.3 UML notation ............................................................................................................................................................................................ 5

5 Conformance ............................................................................................................................................................................................................. 5

5.1 Conformance overview .................................................................................................................................................................... 5

5.2 Conformance classes .......................................................................................................................................................................... 6

5.2.1 General...................................................................................................................................................................................... 6

5.2.2 Data type conformance .............................................................................................................................................. 6

5.2.3 Operation conformance ............................................................................................................................................. 7

6 Linear referencing .............................................................................................................................................................................................. 7

6.1 Background ................................................................................................................................................................................................ 7

6.1.1 Linear referencing concepts .................................................................................................................................. 7

6.1.2 Linear referencing packages ...............................................................................................................................17

6.2 Package: Linear Referencing System .................................................................................................................................18

6.2.1 Semantics ............................................................................................................................................................................18

6.2.2 PositionExpression .....................................................................................................................................................19

6.2.3 LinearElement ...................................................................... ...........................................................................................20

6.2.4 LinearElementType ....................................................................................................................................................21

6.2.5 ILinearElement ...............................................................................................................................................................21

6.2.6 IFeature .................................................................................................................................................................................22

6.2.7 ISpatial ...................................................................................................................................................................................23

6.2.8 LinearReferencingMethod ....................................................................................................................................24

6.2.9 DistanceAlongDirection ..........................................................................................................................................25

6.2.10 LRMType ..............................................................................................................................................................................25

6.2.11 DistanceExpression ....................................................................................................................................................26

6.2.12 Referent ................................................................................................................................................................................27

6.2.13 ReferentType ....................................................................................................................................................................28

6.2.14 ValueExpression ............................................................................................................................................................29

6.3 Package: Linear Referencing Towards Referent ......................................................................................................30

6.3.1 Semantics ............................................................................................................................................................................30

6.3.2 LRMWithTowardsReferent ..................................................................................................................................30

6.3.3 DistanceExpression ....................................................................................................................................................31

6.4 Package: Linear Referencing Offset ....................................................................................................................................31

6.4.1 Semantics ............................................................................................................................................................................31

6.4.2 LRMWithOffset ...............................................................................................................................................................32

6.4.3 LateralOffsetDirection ..............................................................................................................................................33

6.4.4 VerticalOffsetDirection ............................................................................................................................................34

6.4.5 LateralOffsetDistanceExpression ...................................................................................................................34

6.4.6 LateralOffsetExpression .........................................................................................................................................35

6.4.7 LateralOffsetReferent ........................................................................................................................................... .....36

6.4.8 VerticalOffsetExpression ........................................................................................................................................37

6.4.9 VerticalOffsetReferent ..............................................................................................................................................38

6.4.10 ICrossSectionalConvention ..................................................................................................................................38

6.4.11 ICrossSectionalConventionPart .......................................................................................................................39

6.5 Package: Linear Referencing Offset Vector ..................................................................................................................40

6.5.1 Semantics ............................................................................................................................................................................40

© ISO 2020 – All rights reserved iii
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oSIST prEN ISO 19148:2020
ISO/DIS 19148:2020(E)

6.5.2 VectorOffsetDistanceExpression .....................................................................................................................40

6.5.3 VectorOffsetExpression ...........................................................................................................................................41

6.6 Package: Linearly Located Event ..........................................................................................................................................42

6.6.1 Semantics ............................................................................................................................................................................42

6.6.2 Linearly located event ..............................................................................................................................................43

6.6.3 Event ........................................................................................................................................................................................44

6.6.4 AttributeEvent.................................................................................................................................................................45

6.6.5 FeatureEvent ....................................................................................................................................................................46

6.6.6 EventLocation ..................................................................................................................................................................46

6.6.7 AtLocation ..........................................................................................................................................................................47

6.6.8 FromToLocation ............................................................................................................................................................47

6.6.9 EventTime ...........................................................................................................................................................................48

6.6.10 EventInstant ......................................................................................................................................................................49

6.6.11 EventPeriod .......................................................................................................................................................................49

6.7 Package: Linear Segmentation ...............................................................................................................................................49

6.7.1 Semantics ............................................................................................................................................................................49

6.7.2 SegmentableFeature ..................................................................................................................................................50

6.7.3 LinearSegmentSet ........................................................................................................................................................51

6.7.4 LinearSegment ................................................................................................................................................................53

Annex A (normative) Abstract test suite .......................................................................................................................................................54

Annex B (informative) Generalized model for linear referencing ......................................................................................58

Annex C (informative) Commonly used linear referencing methods and models .............................................61

Annex D (informative) Application Schema example ......................................................................................................................84

Annex E (informative) Event and segmentation examples .........................................................................................................86

Annex F (informative) Backwards compatibility with ISO19148: 2012 ........................................................................94

Bibliography .............................................................................................................................................................................................................................96

iv © ISO 2020 – All rights reserved
---------------------- Page: 6 ----------------------
oSIST prEN ISO 19148:2020
ISO/DIS 19148:2020(E)
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

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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.

This second edition cancels and replaces the first edition (ISO 19148:2012), which has been technically

revised.

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.
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Introduction

This document is a description of the data and operations required to support linear referencing. This

includes Linear Referencing Systems, linearly located events and linear segments.

Linear Referencing Systems enable the specification of positions along linear objects. The approach is

[3]

based upon the Generalized Model for Linear Referencing first standardized within ISO 19133:2005.

This document extends that which was included in ISO 19133, both in functionality and explanation.

ISO 19109 supports features representing discrete objects with attributes having values which apply to

the entire feature. ISO 19123 allows the attribute value to vary, depending upon the location within a

feature, but does not support the assignment of attribute values to a single point or length along a linear

feature. Linearly located events provide the mechanism for specifying attribution of linear objects

when the attribute value varies along the length of a linear feature. A Linear Referencing System is used

to specify where along the linear object each attribute value applies. The same mechanism can be used

to specify where along a linear object another object is located, such as guardrail or a traffic accident.

It is common practice to segment a linear object having linearly located events, based upon one or

more of its attributes. The resultant linear segments are attributed with just the attributes used in

the segmentation process, insuring that the linear segments are homogeneous in value for these

segmenting attributes.
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DRAFT INTERNATIONAL STANDARD ISO/DIS 19148:2020(E)
Geographic information — Linear referencing
1 Scope

This document specifies a conceptual schema for locations relative to a one-dimensional object as

measurement along (and optionally offset from) that object. It defines a description of the data and

operations required to use and support linear referencing.

This document is applicable to transportation, utilities, environmental protection, location-based

services and other applications which define locations relative to linear objects. Most examples

discussed in this document come from the transportation domain for the ease of reading.

2 Normative references

The following referenced documents are indispensable for the application 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, Geographic information — Conceptual schema language
ISO 19107, Geographic information — Spatial schema
ISO 19108, Geographic information — Temporal schema
ISO 19111, Geographic information — Referencing by coordinates
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

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

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
attribute event
value of an attribute of a feature that may apply to only part of the feature

Note 1 to entry: to entry:An attribute event includes the linearly referenced location where the attribute value

applies along the attributed feature.

Note 2 to entry: An attribute event may be qualified by the instant in which, or period during which, the attribute

value applied.
3.2
attributed feature
feature along which an attribute event applies
3.3
direct position

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

[SOURCE: ISO 19136-1:2020, 3.1.20]
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3.4
feature
abstraction of real world phenomena
[SOURCE: ISO 19101-1:2014, 4.1.11]
3.5
feature event
information about the occurrence of a located feature along a locating feature

Note 1 to entry: A feature event includes the linearly referenced location of the located feature along the

locating feature.

Note 2 to entry: A feature event may be qualified by the instant in which, or period during which, the feature

event occurred.
3.6
geometric primitive

geometric object representing a single, connected, homogeneous (isotropic) element of space

Note 1 to entry: Geometric primitives are non-decomposed objects that present information about geometric

configuration. They include points, curves, surfaces, and solids. Many geometric objects behave like primitives

(supporting the same interfaces defined for geometric primitives) but are actually composites composed of some

number of other primitives. General collections may be aggregates and incapable of acting like a primitive (such

as the lines of a complex network, which is not connected and thus incapable of being traceable as a single line).

By this definition, a geometric primitive is topological open, since the boundary points are not isotropic to the

interior points. Geometry is assumed to be closed. For points, the boundary is empty.

[SOURCE: ISO 19107:2019, 3.50]
3.7
height
h, H

distance of a point from a chosen reference surface positive upward along a line perpendicular to

that surface

Note 1 to entry: A height below the reference surface will have a negative value.

Note 2 to entry: Generalization of ellipsoidal height (h) and gravity-related height (H).

[SOURCE: ISO 19111:2019, 3.1:38]
3.8
instant
zero-dimensional geometric primitive representing position in time
Note 1 to entry: The geometry of time is discussed in ISO 19108:2002, 5.2.
[SOURCE: ISO 19108:2002, 4.1.17]
3.9
linear element
one-dimensional object that serves as the axis along which measurements are made
Note 1 to entry: Also known as curvilinear element.

EXAMPLE Feature, such as “road”; curve geometry; directed edge topological primitive

3.10
linear referencing

specification of a location relative to a linear element as a measurement along (and optionally offset

from) that element

Note 1 to entry: An alternative to specifying a location as a two- or three- dimensional spatial position.

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3.11
linear referencing method

manner in which measurements are made along (and optionally offset from) a linear element

3.12
linear referencing system
[1]

set of linear referencing methods and the policies, records and procedures for implementing them

3.13
linear segment

part of a linear feature that is distinguished from the remainder of that feature by a subset of attributes,

each having a single value for the entire part

Note 1 to entry: A linear segment is a one-dimensional object without explicit geometry.

Note 2 to entry: The implicit geometry of the linear segment can be derived from the geometry of the parent

feature.
3.14
linearly located
located using a Linear Referencing System
3.15
linearly located event
occurrence along a feature of an attribute value or another feature

Note 1 to entry: The event location is specified using linearly referenced locations.

Note 2 to entry: A linearly located event may be qualified by the instant in which, or period during which, the

linearly located event occurred.

Note 3 to entry: ISO 19108 limits events to a single instant in time and does not include the specification of a

location.
3.16
linearly referenced location
location whose position is specified using linear referencing
3.17
located feature
linearly located feature
feature that is linearly located along an associated (locating) feature

EXAMPLE A feature “bridge” may be a located feature along the feature “railway” [a locating feature].

3.18
locating feature
linearly locating feature
feature that is used to identify the location of linearly located features

EXAMPLE A feature “road” may be the locating feature for a feature “pedestrian crossing” [a located

feature].
3.19
location
a particular place or position
Note 1 to entry: A location identifies a geographic place.

Note 2 to entry: Additionally, in this document, a location is represented by one of a set of data types that describe

a position, along with metadata about that data, including coordinates (from a coordinate reference system), a

measure (from a Linear Referencing System), or an address (from an address system).

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[SOURCE: ISO 19112:2019, 3.1.3]
3.20
period
one-dimensional geometric primitive representing extent in time
Note 1 to entry: A period is bounded by two different temporal positions.
[SOURCE: ISO 19108:2002, 4.1.27]
3.21
position

data type that describes a point or geometry potentially occupied by an object or person

Note 1 to entry: A direct position is a semantic subtype of position. Direct positions as described can define only

a point and, therefore, not all positions can be represented by a direct position. That is consistent with the “is

type of” relation. An ISO 19107 geometry is also a position, just not a direct position.

[SOURCE: ISO 19133:2005, 4.18]
3.22
spatial position

direct position that is referenced to a two- or three-dimensional coordinate reference system

Note 1 to entry: An alternative to specifying a location as a linearly referenced location.

3.23
temporal position
location relative to a temporal reference system
[SOURCE: ISO 19108:2002, 4.1.34]
3.24
temporal reference system
reference system against which time is measured
[SOURCE: ISO 19108:2002, 4.1.35]
3.25
valid time
time when a fact is true in the abstracted reality
[SOURCE: ISO 19108:2002, 4.1.39]
4 Symbols, abbreviated terms, backwards compatibility, and UML notation
4.1 Symbols and abbreviated terms
CRS Coordinate Reference System
LRM Linear Referencing Method
LRS Linear Referencing System
RDF Resource Description Framework
REST Representational State Transfer
SOAP Single Object Access Protocol
4 © ISO 2020 – All right
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