Information and documentation — Thesauri and interoperability with other vocabularies — Part 2: Interoperability with other vocabularies

ISO 25964-2:2013 is applicable to thesauri and other types of vocabulary that are commonly used for information retrieval. It describes, compares and contrasts the elements and features of these vocabularies that are implicated when interoperability is needed. It gives recommendations for the establishment and maintenance of mappings between multiple thesauri, or between thesauri and other types of vocabularies.

Information et documentation — Thésaurus et interopérabilité avec d'autres vocabulaires — Partie 2: Interopérabilité avec d'autres vocabulaires

Informatika in dokumentacija - Tezavri in interoperabilnost z drugimi slovarji - 2. del: Interoperabilnost z drugimi slovarji

Ta del standarda ISO 25964 obravnava tezavre in druge vrste slovarjev, ki se običajno uporabljajo za pridobivanje informacij. Opisuje in primerja elemente in lastnosti teh slovarjev, ki so pomembni, kadar je potrebna interoperabilnost. Daje priporočila za oblikovanje in vzdrževanje preslikav med več tezavri ali med tezavri in drugimi vrstami slovarjev.

General Information

Status
Published
Publication Date
03-Mar-2013
Current Stage
9093 - International Standard confirmed
Start Date
06-Jun-2018
Completion Date
06-Jun-2018

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INTERNATIONAL ISO
STANDARD 25964-2
First edition
2013-03-15
Information and documentation —
Thesauri and interoperability with other
vocabularies —
Part 2:
Interoperability with other vocabularies
Information et documentation — Thésaurus et interopérabilité avec
d'autres vocabulaires —
Partie 2: Interopérabilité avec d'autres vocabulaires
Reference number
ISO 25964-2:2013(E)
ISO 2013
---------------------- Page: 1 ----------------------
ISO 25964-2:2013(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2013

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,

electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or

ISO's member body in the country of the requester.
ISO copyright office
Case postale 56  CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2013 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 25964-2:2013(E)
Contents Page

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

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

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

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

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

4  Symbols, abbreviations and other conventions .............................................................................. 15

5  Objectives and identification ............................................................................................................. 16

5.1  Objectives of interoperability and mapping ..................................................................................... 16

5.2  Identifying the elements to be mapped ............................................................................................. 16

6  Structural models for mapping across vocabularies ...................................................................... 16

6.1  General ................................................................................................................................................. 16

6.2  Model 1: Structural unity .................................................................................................................... 17

6.3  Model 2: Direct-linked ......................................................................................................................... 17

6.4  Model 3: Hub structure ....................................................................................................................... 17

6.5  Selective mapping ............................................................................................................................... 19

6.6  Choosing among the options ............................................................................................................. 20

7  Types of mapping ................................................................................................................................ 20

7.1  General ................................................................................................................................................. 20

8  Equivalence mappings........................................................................................................................ 21

8.1  General ................................................................................................................................................. 21

8.2  Simple equivalence ............................................................................................................................. 21

8.3  Compound equivalence ...................................................................................................................... 22

9  Hierarchical mappings ........................................................................................................................ 25

10  Associative mappings......................................................................................................................... 25

11  Exact, inexact and partial equivalence.............................................................................................. 26

11.1  General ................................................................................................................................................. 26

11.2  Exact equivalence ............................................................................................................................... 26

11.3  Inexact equivalence ............................................................................................................................. 27

11.4  Partial equivalence .............................................................................................................................. 27

12  Use of mappings in information retrieval ......................................................................................... 28

12.1  General ................................................................................................................................................. 28

12.2  Human mediation ................................................................................................................................ 28

12.3  Examples of mapping implementation .............................................................................................. 29

12.4  Conclusions and recommendations ................................................................................................. 30

13  Handling pre-coordination ................................................................................................................. 31

13.1  General ................................................................................................................................................. 31

13.2  Mapping between a thesaurus and a scheme with context-dependent captions ........................ 32

13.3  Mapping more complex classes ........................................................................................................ 37

14  Techniques for identifying candidate mappings ............................................................................. 38

14.1  General procedure ............................................................................................................................... 38

14.2  Computer assisted direct matching .................................................................................................. 40

14.3  Co-occurrence mapping ..................................................................................................................... 40

14.4  Other methods ..................................................................................................................................... 40

15  Managing the data ............................................................................................................................... 41

15.1  Types of data to be recorded ............................................................................................................. 41

15.2  Storing the data ................................................................................................................................... 43

15.3  Maintaining the mappings data .......................................................................................................... 43

© ISO 2013 – All rights reserved iii
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ISO 25964-2:2013(E)

16  Display of mapped vocabularies ........................................................................................................45

16.1  General ..................................................................................................................................................45

16.2  Single record display ..........................................................................................................................46

16.3  Complete displays based on one of the vocabularies .....................................................................48

16.4  Crosswalks ...........................................................................................................................................49

17  Classification schemes .......................................................................................................................50

17.1  Key characteristics and background .................................................................................................50

17.2  Semantic components and relationships compared with thesaurus components ......................53

17.3  Recommendations for mapping between a thesaurus and a classification scheme ...................55

18  Classification schemes used for records management ..................................................................56

18.1  Key characteristics and background .................................................................................................56

18.2  Semantic components and relationships compared with thesaurus components ......................57

18.3  Recommendations for interoperability with a thesaurus ................................................................58

19  Taxonomies ..........................................................................................................................................59

19.1  Key characteristics and background .................................................................................................59

19.2  Types of taxonomies ...........................................................................................................................60

19.3  Semantic components and relationships .........................................................................................61

19.4  Mapping between a thesaurus and a taxonomy ...............................................................................63

20  Subject heading schemes ...................................................................................................................67

20.1  Key characteristics and background .................................................................................................67

20.2  Semantic components and relationships .........................................................................................68

20.3  Mapping subject headings to and from thesaurus concepts .........................................................69

21  Ontologies ............................................................................................................................................72

21.1  Key characteristics and background .................................................................................................72

21.2  Semantic components and relationships .........................................................................................73

21.3  Structural comparison between thesauri and ontologies ...............................................................76

21.4  Interoperability with thesauri ..............................................................................................................77

22  Terminologies ......................................................................................................................................78

22.1  Key characteristics and background .................................................................................................78

22.2  Semantic components and relationships compared with those of a thesaurus ..........................79

22.3  Interoperability with thesauri ..............................................................................................................81

23  Name authority lists ............................................................................................................................81

23.1  Key characteristics and background .................................................................................................81

23.2  Semantic components and relationships .........................................................................................83

23.3  Mapping between a thesaurus and a name authority list ................................................................85

24  Synonym rings .....................................................................................................................................87

24.1  Key characteristics and background .................................................................................................87

24.2  Semantic components and relationships .........................................................................................88

24.3  Interoperability with thesauri ..............................................................................................................89

Annex A (informative) Management of terminological data in support of interoperability .......................90

Bibliography ......................................................................................................................................................93

Index ...................................................................................................................................................................96

iv © ISO 2013 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 25964-2:2013(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.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standards

adopted by the technical committees are circulated to the member bodies for voting. Publication as an

International Standard requires approval by at least 75 % of the member bodies casting a vote.

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.

ISO 25964-2 was prepared by Technical Committee ISO/TC 46, Information and documentation,

Subcommittee SC 9, Identification and description.

ISO 25964-1:2011, Clauses 1 to 13, correspond broadly to the content of ISO 2788:1986 and ISO 5964:1985.

The remaining clauses of ISO 25964-1, and the whole of this part of ISO 25964, cover new ground not

previously covered in any International Standard.

ISO 25964 consists of the following parts, under the general title Information and documentation — Thesauri

and interoperability with other vocabularies:
— Part 1: Thesauri for information retrieval
— Part 2: Interoperability with other vocabularies

ISO 25964-1 covers the development and maintenance of thesauri, both monolingual and multilingual,

including formats and protocols for data exchange.

This part of ISO 25964 covers interoperability between different thesauri and with other types of structured

vocabulary.

ISO 25964 covers development and maintenance of thesauri rather than how to use them in indexing, which

is covered by ISO 999.
© ISO 2013 – All rights reserved v
---------------------- Page: 5 ----------------------
ISO 25964-2:2013(E)
Introduction

The ability to identify and locate relevant information among vast collections and other resources is a major

and pressing challenge today, hence the need for semantic interoperability. To support this need, a variety of

web services and other tools are under active development, including (but not limited to):

 registries of vocabularies and metadata schemas,
 repositories of vocabularies and metadata schemas, and
 crosswalk services.

While registries and repositories are outside the scope, this International Standard provides guidance

fundamental to the establishment of crosswalk services. Typically these rely on mapping between different

schemas and vocabularies. Accordingly, inter-vocabulary mapping will be the principal focus of this part of

ISO 25964.

The foundation for discussion of interoperability is laid in ISO 25964-1, which describes the key characteristics

of thesauri and provides guidance on best practice. Unfortunately, however, a comparable International

Standard does not exist for the other types of vocabulary with which a thesaurus needs to interoperate. For

this reason, this second part of ISO 25964 provides some elementary description of other vocabularies such

as classification schemes, subject heading schemes, etc., before making recommendations on mapping

between these and thesauri. It does not provide guidance on the construction of vocabularies other than

thesauri.

Clauses 1 to 12 and Clauses 14 to 16 of this part of ISO 25964 deal with the principles and practicalities of

interoperability, especially mapping, that apply to most vocabularies and especially thesauri. Clause 13

provides additional guidance for handling the pre-coordinated classes that occur in classification schemes and

other vocabularies using the classification approach.

Clauses 17 to 24 are each dedicated to a different type of vocabulary. First priority is given to vocabularies

that are commonly used for classifying or indexing resources, namely classification schemes (including those

used for records management), taxonomies, subject heading schemes and name authority lists.

Notwithstanding their different purposes, terminologies, ontologies and synonym rings are also included. Each

clause provides a brief informative description of the vocabulary’s key characteristics, contrasting its semantic

components with those of a thesaurus, so as to provide context for the interoperability requirements and

recommendations that follow.
vi © ISO 2013 – All rights reserved
---------------------- Page: 6 ----------------------
INTERNATIONAL STANDARD ISO 25964-2:2013(E)
Information and documentation — Thesauri and interoperability
with other vocabularies —
Part 2:
Interoperability with other vocabularies
1 Scope

This part of ISO 25964 is applicable to thesauri and other types of vocabulary that are commonly used for

information retrieval. It describes, compares and contrasts the elements and features of these vocabularies

that are implicated when interoperability is needed. It gives recommendations for the establishment and

maintenance of mappings between multiple thesauri, or between thesauri and other types of vocabularies.

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 25964-1:2011, Information and documentation — Thesauri and interoperability with other vocabularies —

Part 1: Thesauri for information retrieval
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
array
group of sibling concepts (3.17)
EXAMPLE

In the following, the sibling concepts outerwear and underwear form an array within the concept clothing.

clothing
outerwear
overcoats
underwear
3.2
associative relationship

relationship between a pair of concepts (3.17) that are not related hierarchically but share a strong semantic

connection
© ISO 2013 – All rights reserved 1
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ISO 25964-2:2013(E)
3.3
broader term

preferred term (3.62) representing a concept (3.17) that is broader than the one in question

NOTE The scope of the narrower concept falls completely within the scope of the broader. The relationship between

the two is commonly indicated with the tag BT. For more explanation see ISO 25964-1:2011, 10.2.1.

3.4
caption

text label of the class (3.10) represented by a notation (3.54) in a classification scheme (3.12)

NOTE A caption is read in conjunction with its hierarchical context. It does not need to be as complete or as

self-contained as a scope note or even a preferred term in a thesaurus. Captions are sometimes known as class headings

or class names.
3.5
category

concept (3.17) or group of similar or related concepts (3.17) used as a division or subdivision in a taxonomy

(3.83)
NOTE 1 In a classification scheme, such a group is normally called a class.

NOTE 2 This definition of category should not be confused with “fundamental categories”, discussed in

ISO 25964-1:2011 (for example in Clause 12) in the context of faceted classification.

3.6
category label
text label representing a category (3.5) in a taxonomy (3.83)

NOTE The category label in a taxonomy is comparable to the caption in a classification scheme, and although a

category is often referred to as a node, a category label should not be confused with a node label.

3.7
chain index

index to a scheme that represents compound concepts (3.17) by a string of pre-coordinated (3.60) terms

(3.84), such as a classification scheme (3.12), in which entries are generated by successive left truncation

of strings of terms (3.84) representing complex concepts (3.17)
NOTE See the example in 17.2.4, Figure 12.
3.8
characteristic of division

attribute by which a concept (3.17) can be subdivided into an array (3.1) of narrower concepts (3.17) each

having a distinct value of that attribute
cf. node label (3.52)
EXAMPLE

In the following, age group is the characteristic of division applied to the concept of people.

people
(people by age group)
children
youths
adults
3.9
citation order

order in which preferred terms (3.62) or notations (3.54) are combined in a pre-coordinate (3.60) indexing

(3.36) system or a classification scheme (3.12) to form strings representing complex concepts (3.17)

2 © ISO 2013 – All rights reserved
---------------------- Page: 8 ----------------------
ISO 25964-2:2013(E)
3.10
class

concept (3.17) or group of similar or related concepts (3.17) used as a division or subdivision in a

classification scheme (3.12)

NOTE Classes are the basic units of which a classification scheme is constructed. In a taxonomy, although this is a

type of classification scheme, they are generally known as categories (see 3.5). Occasionally they are described as

“nodes”, although they should not be confused with node labels. The term “class” has a different meaning in the context of

ontologies. See 21.2.2.
3.11
classification
classifying

activity involving the components of grouping similar or related things together, separating dissimilar or

unrelated things, and arranging the resulting classes (3.10) in a logical and helpful sequence

3.12
classification scheme

schedule (3.67) of concepts (3.17) and pre-coordinated (3.60) combinations of concepts (3.17), arranged

by classification (3.11)
NOTE A classification scheme often also includes an index.
3.13
collection

set of information resources that can or could be accessed by a structured vocabulary (3.74), whether the

items in the set are collected in one place or distributed over a network
3.14
compound equivalence

relationship between terms (3.84) or mapping (3.41) between concepts (3.17) in which one term (3.84) or

concept (3.17) in one context is represented by two or more terms (3.84) or concepts (3.17) in another

3.15
compound heading
pre-coordinated heading

subject heading (3.76) formed by pre-coordination (3.60) of more than one term (3.84) into a string

EXAMPLE

The single terms Buddhism, Mass media and Religious aspects may be combined to form the compound heading

Mass media — Religious aspects — Buddhism.
3.16
compound term
term (3.84) that can be split morphologically into separate components
EXAMPLES
In English:
“copper mines” can be split into “copper” and “mines”
“lawnmowers” can be split into “lawns” and “mowers”
In French:
“mine de cuivre” can be split into “mine” and “cuivre”
“biodiversité” can be split into “biologie” and “diversité”
NOTE Compound terms can be multi-word terms, or can consist of only one word.
© ISO 2013 – All rights reserved 3
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ISO 25964-2:2013(E)
3.17
concept
unit of thought

NOTE Concepts can be expressed in a variety of different ways. They exist in the mind as abstract entities

independent of terms used to express them. They range from the very simple, e.g. “child”, to the very complex, e.g. “child

protection legislation”.
3.18
concept group

group of concepts (3.17) selected by some specified criterion, such as relevance to a particular subject area

3.19
controlled vocabulary

prescribed list of terms (3.84), headings or codes, each representing a concept (3.17)

NOTE Controlled vocabularies are designed for applications in which it is useful to identify each concept with one

consistent label, for example when classifying documents, indexing them and/or searching them. Thesauri, subject

heading schemes and name authority lists are examples of controlled vocabularies.

cf. terminology (3.85)
3.20
cross-language equivalence

equivalence relationship (3.28) between terms (3.84) representing the same concept (3.17) in different

languages
3.21
crosswalk

table of mappings (3.41) between the concepts (3.17) in two or more structured vocabularies (3.74)

NOTE Crosswalks support the ability of search engines to search effectively across heterogeneous databases.

3.22
data model
abstract model that describes how data is represented and used

NOTE The data model in ISO 25964-1 provides a generic definition of thesaurus structure and semantics. It can be

used as the basis for defining a database model or an exchange format for thesauri.

3.23
differentiated mapping

mapping (3.40) methodology that aims to distinguish between different types and qualities of mapping (3.41)

NOTE Types of mapping that can be distinguished include equivalence, associative and hierarchical; equivalence

can be further subdivided into simple or compound, and the degree of equivalence can be marked to support further

distinctions at the time of use.
cf. undifferentiated mapping (3.88)
3.24
document

any resource that can be classified (3.11) or indexed in order that the data or information in it may be

retrieved

NOTE This definition refers not only to written and printed materials in paper or microform versions (for example,

conventional books, journals, diagrams, maps), but also to non-printed media such as machine-readable and digitized

records, internet and intranet resources, films, sound recordings, people and organizations as knowledge resources,

buildings, sites, monuments, three-dimensional objects or realia; and collections of such items or parts of such items.

4 © ISO 2013 – All rights reserved
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ISO 25964-2:2013(E)
3.25
entry term
lead-in term

term (3.84) provided in a controlled vocabulary (3.19), not for direct use in metadata (3.45), but for the

purpose of guiding the user to another term (3.84) which may be used as a category label (3.6), subject

heading (3.76) or preferred term (3.62)

NOTE Entry terms occurring in a thesaurus are generally known as non-preferred terms.

3.26
enumerative classification scheme

classification scheme (3.12) in which all the classes (3.10) available are explicitly listed in the schedules

(3.67)
cf. synthetic classification scheme (3.80)
3.27
equivalence mapping

mapping (3.41) that states that the concept (3.17) in the target vocabulary (3.82) is considered identical in

scope to the concept (3.17) in the source vocabulary (3.72)
cf. equivalence relationship (3.28)
3.28
equivalence relationship

relationship between two terms (3.84) in a thesaurus (3.86) that both represent the same concept (3.17)

NOTE In ordinary discourse, terms that are quasi-synonyms may represent slightly different concepts. After inclusion

in the thesaurus, however, the equivalence relationship clarifies that both are regarded as representing the same concept.

When two or more such terms are in the same language within a monolingual or multilingual thesaurus, one of them is

designated a preferred term and the other(s) as non-preferred term(s); when two or more such terms are in the different

languages of a multilingual thesaurus, each of them may be a preferred term in i
...

SLOVENSKI STANDARD
SIST ISO 25964-2:2013
01-julij-2013

Informatika in dokumentacija - Tezavri in interoperabilnost z drugimi slovarji - 2.

del: Interoperabilnost z drugimi slovarji

Information and documentation -- Thesauri and interoperability with other vocabularies --

Part 2: Interoperability with other vocabularies

Information et documentation -- Thésaurus et interopérabilité avec d'autres vocabulaires

-- Partie 2: Interopérabilité avec d'autres vocabulaires
Ta slovenski standard je istoveten z: ISO 25964-2:2013
ICS:
01.140.20 Informacijske vede Information sciences
SIST ISO 25964-2:2013 en,fr,de

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

---------------------- Page: 1 ----------------------
SIST ISO 25964-2:2013
---------------------- Page: 2 ----------------------
SIST ISO 25964-2:2013
INTERNATIONAL ISO
STANDARD 25964-2
First edition
2013-03-15
Information and documentation —
Thesauri and interoperability with other
vocabularies —
Part 2:
Interoperability with other vocabularies
Information et documentation — Thésaurus et interopérabilité avec
d'autres vocabulaires —
Partie 2: Interopérabilité avec d'autres vocabulaires
Reference number
ISO 25964-2:2013(E)
ISO 2013
---------------------- Page: 3 ----------------------
SIST ISO 25964-2:2013
ISO 25964-2:2013(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2013

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,

electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or

ISO's member body in the country of the requester.
ISO copyright office
Case postale 56  CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2013 – All rights reserved
---------------------- Page: 4 ----------------------
SIST ISO 25964-2:2013
ISO 25964-2:2013(E)
Contents Page

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

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

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

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

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

4  Symbols, abbreviations and other conventions .............................................................................. 15

5  Objectives and identification ............................................................................................................. 16

5.1  Objectives of interoperability and mapping ..................................................................................... 16

5.2  Identifying the elements to be mapped ............................................................................................. 16

6  Structural models for mapping across vocabularies ...................................................................... 16

6.1  General ................................................................................................................................................. 16

6.2  Model 1: Structural unity .................................................................................................................... 17

6.3  Model 2: Direct-linked ......................................................................................................................... 17

6.4  Model 3: Hub structure ....................................................................................................................... 17

6.5  Selective mapping ............................................................................................................................... 19

6.6  Choosing among the options ............................................................................................................. 20

7  Types of mapping ................................................................................................................................ 20

7.1  General ................................................................................................................................................. 20

8  Equivalence mappings........................................................................................................................ 21

8.1  General ................................................................................................................................................. 21

8.2  Simple equivalence ............................................................................................................................. 21

8.3  Compound equivalence ...................................................................................................................... 22

9  Hierarchical mappings ........................................................................................................................ 25

10  Associative mappings......................................................................................................................... 25

11  Exact, inexact and partial equivalence.............................................................................................. 26

11.1  General ................................................................................................................................................. 26

11.2  Exact equivalence ............................................................................................................................... 26

11.3  Inexact equivalence ............................................................................................................................. 27

11.4  Partial equivalence .............................................................................................................................. 27

12  Use of mappings in information retrieval ......................................................................................... 28

12.1  General ................................................................................................................................................. 28

12.2  Human mediation ................................................................................................................................ 28

12.3  Examples of mapping implementation .............................................................................................. 29

12.4  Conclusions and recommendations ................................................................................................. 30

13  Handling pre-coordination ................................................................................................................. 31

13.1  General ................................................................................................................................................. 31

13.2  Mapping between a thesaurus and a scheme with context-dependent captions ........................ 32

13.3  Mapping more complex classes ........................................................................................................ 37

14  Techniques for identifying candidate mappings ............................................................................. 38

14.1  General procedure ............................................................................................................................... 38

14.2  Computer assisted direct matching .................................................................................................. 40

14.3  Co-occurrence mapping ..................................................................................................................... 40

14.4  Other methods ..................................................................................................................................... 40

15  Managing the data ............................................................................................................................... 41

15.1  Types of data to be recorded ............................................................................................................. 41

15.2  Storing the data ................................................................................................................................... 43

15.3  Maintaining the mappings data .......................................................................................................... 43

© ISO 2013 – All rights reserved iii
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SIST ISO 25964-2:2013
ISO 25964-2:2013(E)

16  Display of mapped vocabularies ........................................................................................................45

16.1  General ..................................................................................................................................................45

16.2  Single record display ..........................................................................................................................46

16.3  Complete displays based on one of the vocabularies .....................................................................48

16.4  Crosswalks ...........................................................................................................................................49

17  Classification schemes .......................................................................................................................50

17.1  Key characteristics and background .................................................................................................50

17.2  Semantic components and relationships compared with thesaurus components ......................53

17.3  Recommendations for mapping between a thesaurus and a classification scheme ...................55

18  Classification schemes used for records management ..................................................................56

18.1  Key characteristics and background .................................................................................................56

18.2  Semantic components and relationships compared with thesaurus components ......................57

18.3  Recommendations for interoperability with a thesaurus ................................................................58

19  Taxonomies ..........................................................................................................................................59

19.1  Key characteristics and background .................................................................................................59

19.2  Types of taxonomies ...........................................................................................................................60

19.3  Semantic components and relationships .........................................................................................61

19.4  Mapping between a thesaurus and a taxonomy ...............................................................................63

20  Subject heading schemes ...................................................................................................................67

20.1  Key characteristics and background .................................................................................................67

20.2  Semantic components and relationships .........................................................................................68

20.3  Mapping subject headings to and from thesaurus concepts .........................................................69

21  Ontologies ............................................................................................................................................72

21.1  Key characteristics and background .................................................................................................72

21.2  Semantic components and relationships .........................................................................................73

21.3  Structural comparison between thesauri and ontologies ...............................................................76

21.4  Interoperability with thesauri ..............................................................................................................77

22  Terminologies ......................................................................................................................................78

22.1  Key characteristics and background .................................................................................................78

22.2  Semantic components and relationships compared with those of a thesaurus ..........................79

22.3  Interoperability with thesauri ..............................................................................................................81

23  Name authority lists ............................................................................................................................81

23.1  Key characteristics and background .................................................................................................81

23.2  Semantic components and relationships .........................................................................................83

23.3  Mapping between a thesaurus and a name authority list ................................................................85

24  Synonym rings .....................................................................................................................................87

24.1  Key characteristics and background .................................................................................................87

24.2  Semantic components and relationships .........................................................................................88

24.3  Interoperability with thesauri ..............................................................................................................89

Annex A (informative) Management of terminological data in support of interoperability .......................90

Bibliography ......................................................................................................................................................93

Index ...................................................................................................................................................................96

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SIST ISO 25964-2:2013
ISO 25964-2:2013(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.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standards

adopted by the technical committees are circulated to the member bodies for voting. Publication as an

International Standard requires approval by at least 75 % of the member bodies casting a vote.

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.

ISO 25964-2 was prepared by Technical Committee ISO/TC 46, Information and documentation,

Subcommittee SC 9, Identification and description.

ISO 25964-1:2011, Clauses 1 to 13, correspond broadly to the content of ISO 2788:1986 and ISO 5964:1985.

The remaining clauses of ISO 25964-1, and the whole of this part of ISO 25964, cover new ground not

previously covered in any International Standard.

ISO 25964 consists of the following parts, under the general title Information and documentation — Thesauri

and interoperability with other vocabularies:
— Part 1: Thesauri for information retrieval
— Part 2: Interoperability with other vocabularies

ISO 25964-1 covers the development and maintenance of thesauri, both monolingual and multilingual,

including formats and protocols for data exchange.

This part of ISO 25964 covers interoperability between different thesauri and with other types of structured

vocabulary.

ISO 25964 covers development and maintenance of thesauri rather than how to use them in indexing, which

is covered by ISO 999.
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Introduction

The ability to identify and locate relevant information among vast collections and other resources is a major

and pressing challenge today, hence the need for semantic interoperability. To support this need, a variety of

web services and other tools are under active development, including (but not limited to):

 registries of vocabularies and metadata schemas,
 repositories of vocabularies and metadata schemas, and
 crosswalk services.

While registries and repositories are outside the scope, this International Standard provides guidance

fundamental to the establishment of crosswalk services. Typically these rely on mapping between different

schemas and vocabularies. Accordingly, inter-vocabulary mapping will be the principal focus of this part of

ISO 25964.

The foundation for discussion of interoperability is laid in ISO 25964-1, which describes the key characteristics

of thesauri and provides guidance on best practice. Unfortunately, however, a comparable International

Standard does not exist for the other types of vocabulary with which a thesaurus needs to interoperate. For

this reason, this second part of ISO 25964 provides some elementary description of other vocabularies such

as classification schemes, subject heading schemes, etc., before making recommendations on mapping

between these and thesauri. It does not provide guidance on the construction of vocabularies other than

thesauri.

Clauses 1 to 12 and Clauses 14 to 16 of this part of ISO 25964 deal with the principles and practicalities of

interoperability, especially mapping, that apply to most vocabularies and especially thesauri. Clause 13

provides additional guidance for handling the pre-coordinated classes that occur in classification schemes and

other vocabularies using the classification approach.

Clauses 17 to 24 are each dedicated to a different type of vocabulary. First priority is given to vocabularies

that are commonly used for classifying or indexing resources, namely classification schemes (including those

used for records management), taxonomies, subject heading schemes and name authority lists.

Notwithstanding their different purposes, terminologies, ontologies and synonym rings are also included. Each

clause provides a brief informative description of the vocabulary’s key characteristics, contrasting its semantic

components with those of a thesaurus, so as to provide context for the interoperability requirements and

recommendations that follow.
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SIST ISO 25964-2:2013
INTERNATIONAL STANDARD ISO 25964-2:2013(E)
Information and documentation — Thesauri and interoperability
with other vocabularies —
Part 2:
Interoperability with other vocabularies
1 Scope

This part of ISO 25964 is applicable to thesauri and other types of vocabulary that are commonly used for

information retrieval. It describes, compares and contrasts the elements and features of these vocabularies

that are implicated when interoperability is needed. It gives recommendations for the establishment and

maintenance of mappings between multiple thesauri, or between thesauri and other types of vocabularies.

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 25964-1:2011, Information and documentation — Thesauri and interoperability with other vocabularies —

Part 1: Thesauri for information retrieval
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
array
group of sibling concepts (3.17)
EXAMPLE

In the following, the sibling concepts outerwear and underwear form an array within the concept clothing.

clothing
outerwear
overcoats
underwear
3.2
associative relationship

relationship between a pair of concepts (3.17) that are not related hierarchically but share a strong semantic

connection
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3.3
broader term

preferred term (3.62) representing a concept (3.17) that is broader than the one in question

NOTE The scope of the narrower concept falls completely within the scope of the broader. The relationship between

the two is commonly indicated with the tag BT. For more explanation see ISO 25964-1:2011, 10.2.1.

3.4
caption

text label of the class (3.10) represented by a notation (3.54) in a classification scheme (3.12)

NOTE A caption is read in conjunction with its hierarchical context. It does not need to be as complete or as

self-contained as a scope note or even a preferred term in a thesaurus. Captions are sometimes known as class headings

or class names.
3.5
category

concept (3.17) or group of similar or related concepts (3.17) used as a division or subdivision in a taxonomy

(3.83)
NOTE 1 In a classification scheme, such a group is normally called a class.

NOTE 2 This definition of category should not be confused with “fundamental categories”, discussed in

ISO 25964-1:2011 (for example in Clause 12) in the context of faceted classification.

3.6
category label
text label representing a category (3.5) in a taxonomy (3.83)

NOTE The category label in a taxonomy is comparable to the caption in a classification scheme, and although a

category is often referred to as a node, a category label should not be confused with a node label.

3.7
chain index

index to a scheme that represents compound concepts (3.17) by a string of pre-coordinated (3.60) terms

(3.84), such as a classification scheme (3.12), in which entries are generated by successive left truncation

of strings of terms (3.84) representing complex concepts (3.17)
NOTE See the example in 17.2.4, Figure 12.
3.8
characteristic of division

attribute by which a concept (3.17) can be subdivided into an array (3.1) of narrower concepts (3.17) each

having a distinct value of that attribute
cf. node label (3.52)
EXAMPLE

In the following, age group is the characteristic of division applied to the concept of people.

people
(people by age group)
children
youths
adults
3.9
citation order

order in which preferred terms (3.62) or notations (3.54) are combined in a pre-coordinate (3.60) indexing

(3.36) system or a classification scheme (3.12) to form strings representing complex concepts (3.17)

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3.10
class

concept (3.17) or group of similar or related concepts (3.17) used as a division or subdivision in a

classification scheme (3.12)

NOTE Classes are the basic units of which a classification scheme is constructed. In a taxonomy, although this is a

type of classification scheme, they are generally known as categories (see 3.5). Occasionally they are described as

“nodes”, although they should not be confused with node labels. The term “class” has a different meaning in the context of

ontologies. See 21.2.2.
3.11
classification
classifying

activity involving the components of grouping similar or related things together, separating dissimilar or

unrelated things, and arranging the resulting classes (3.10) in a logical and helpful sequence

3.12
classification scheme

schedule (3.67) of concepts (3.17) and pre-coordinated (3.60) combinations of concepts (3.17), arranged

by classification (3.11)
NOTE A classification scheme often also includes an index.
3.13
collection

set of information resources that can or could be accessed by a structured vocabulary (3.74), whether the

items in the set are collected in one place or distributed over a network
3.14
compound equivalence

relationship between terms (3.84) or mapping (3.41) between concepts (3.17) in which one term (3.84) or

concept (3.17) in one context is represented by two or more terms (3.84) or concepts (3.17) in another

3.15
compound heading
pre-coordinated heading

subject heading (3.76) formed by pre-coordination (3.60) of more than one term (3.84) into a string

EXAMPLE

The single terms Buddhism, Mass media and Religious aspects may be combined to form the compound heading

Mass media — Religious aspects — Buddhism.
3.16
compound term
term (3.84) that can be split morphologically into separate components
EXAMPLES
In English:
“copper mines” can be split into “copper” and “mines”
“lawnmowers” can be split into “lawns” and “mowers”
In French:
“mine de cuivre” can be split into “mine” and “cuivre”
“biodiversité” can be split into “biologie” and “diversité”
NOTE Compound terms can be multi-word terms, or can consist of only one word.
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3.17
concept
unit of thought

NOTE Concepts can be expressed in a variety of different ways. They exist in the mind as abstract entities

independent of terms used to express them. They range from the very simple, e.g. “child”, to the very complex, e.g. “child

protection legislation”.
3.18
concept group

group of concepts (3.17) selected by some specified criterion, such as relevance to a particular subject area

3.19
controlled vocabulary

prescribed list of terms (3.84), headings or codes, each representing a concept (3.17)

NOTE Controlled vocabularies are designed for applications in which it is useful to identify each concept with one

consistent label, for example when classifying documents, indexing them and/or searching them. Thesauri, subject

heading schemes and name authority lists are examples of controlled vocabularies.

cf. terminology (3.85)
3.20
cross-language equivalence

equivalence relationship (3.28) between terms (3.84) representing the same concept (3.17) in different

languages
3.21
crosswalk

table of mappings (3.41) between the concepts (3.17) in two or more structured vocabularies (3.74)

NOTE Crosswalks support the ability of search engines to search effectively across heterogeneous databases.

3.22
data model
abstract model that describes how data is represented and used

NOTE The data model in ISO 25964-1 provides a generic definition of thesaurus structure and semantics. It can be

used as the basis for defining a database model or an exchange format for thesauri.

3.23
differentiated mapping

mapping (3.40) methodology that aims to distinguish between different types and qualities of mapping (3.41)

NOTE Types of mapping that can be distinguished include equivalence, associative and hierarchical; equivalence

can be further subdivided into simple or compound, and the degree of equivalence can be marked to support further

distinctions at the time of use.
cf. undifferentiated mapping (3.88)
3.24
document

any resource that can be classified (3.11) or indexed in order that the data or information in it may be

retrieved

NOTE This definition refers not only to written and printed materials in paper or microform versions (for example,

conventional books, journals, diagrams, maps), but also to non-printed media such as machine-readable and digitized

records, internet and intranet resources, films, sound recordings, people and organizations as knowledge resources,

buildings, sites, monuments, three-dimensional objects or realia; and collections of such items or parts of such items.

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3.25
entry term
lead-in term

term (3.84) provided in a controlled vocabulary (3.19), not for direct use in metadata (3.45), but for the

purpose of guiding the user to another term (3.84) which may be used as a category label (3.6), subject

heading (3.76) or preferred term (3.62)

NOTE Entry terms occurring in a thesaurus are generally known as non-preferred terms.

3.26
enumera
...

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