ISO/TS 19139:2007

Geographic information — Metadata — XML schema implementation

ISO/TS 19139:2007 defines Geographic MetaData XML (gmd) encoding, an XML Schema implementation derived from ISO 19115.

Information géographique — Métadonnées — Implémentation de schémas XML

General Information

• Status: Withdrawn
• Publication Date: 16-Apr-2007
• Withdrawal Date: 16-Apr-2007
• ICS: 35.240.70 - IT applications in science
• Technical Committee: ISO/TC 211 - Geographic information/Geomatics
• Drafting Committee: ISO/TC 211/WG 7 - Information communities
• Current Stage: 9599 - Withdrawal of International Standard
• Completion Date: 25-Feb-2019

Relations

• Revised: ISO/TS 19139-1:2019 - Geographic information — XML schema implementation — Part 1: Encoding rules
• Effective Date: 16-Aug-2014

Standards Content (Sample)

TECHNICAL ISO/TS
SPECIFICATION 19139
First edition
2007-04-15

Geographic information — Metadata —
XML schema implementation
Information géographique — Métadonnées — Implémentation de
schémas XML




Reference number
ISO/TS 19139:2007(E)
©
ISO 2007

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ISO/TS 19139:2007(E)
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ISO/TS 19139:2007(E)
Contents Page
Foreword .iv
Introduction.v
1 Scope.1
2 Conformance .1
3 Normative references.1
4 Terms and definitions .2
5 Symbols and abbreviated terms .3
5.1 Acronyms .3
5.2 Namespace abbreviations .3
5.3 UML model relationships.3
5.4 UML model stereotypes.4
6 Requirements.5
6.1 Introduction to gmd.5
6.2 Rule-based .5
6.3 Quality .6
6.4 Web implementations .6
6.5 Use of external XML implementations .6
6.6 Multilingual support .6
6.7 Polymorphism.7
6.8 Rules for application schema .7
7 Extensions to the UML models in the ISO 19100 series of International Standards.8
7.1 Introduction to extensions .8
7.2 Extensions specific to the web environment .8
7.3 Cultural and linguistic adaptability extensions.9
7.4 Extensions for metadata-based transfers of geospatial information .11
8 Encoding rules.17
8.1 Introduction to encoding rules .17
8.2 Default XML Class Type encoding.17
8.3 XML Class Global Element encoding.20
8.4 XML Class Property Type encoding.20
8.5 Special case encodings.22
8.6 XML namespace package encoding.40
8.7 XML schema package encoding.41
9 Encoding descriptions.43
9.1 Introduction to the encoding descriptions .43
9.2 XML namespaces .43
9.3 gmd namespace .44
9.4 gss namespace.50
9.5 gts namespace.52
9.6 gsr namespace .53
9.7 gco namespace.54
9.8 gmx namespace.65
9.9 From the conceptual schema to XML file instances.72
Annex A (normative) Abstract test suite .74
Annex B (normative) Data dictionary for extensions.77
Annex C (informative) Geographic Metadata XML resources .87
Annex D (informative) Implementation examples.89
Bibliography.111
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ISO/TS 19139:2007(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.
In other circumstances, particularly when there is an urgent market requirement for such documents, a
technical committee may decide to publish other types of normative document:
⎯ an ISO Publicly Available Specification (ISO/PAS) represents an agreement between technical experts in
an ISO working group and is accepted for publication if it is approved by more than 50 % of the members
of the parent committee casting a vote;
⎯ an ISO Technical Specification (ISO/TS) represents an agreement between the members of a technical
committee and is accepted for publication if it is approved by 2/3 of the members of the committee casting
a vote.
An ISO/PAS or ISO/TS is reviewed after three years in order to decide whether it will be confirmed for a
further three years, revised to become an International Standard, or withdrawn. If the ISO/PAS or ISO/TS is
confirmed, it is reviewed again after a further three years, at which time it must either be transformed into an
International Standard or be withdrawn.
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/TS 19139 was prepared by Technical Committee ISO/TC 211, Geographic information/Geomatics.
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ISO/TS 19139:2007(E)
Introduction
The importance of metadata describing digital geographic data is explained in detail in the text of ISO 19115.
ISO 19115 provides a structure for describing digital geographic data by defining metadata elements and
establishing a common set of metadata terminology, definitions and extension procedures. ISO 19115 is
abstract in that it provides a worldwide view of metadata relative to geographic information, but no encoding.
Since ISO 19115 does not provide any encoding, the actual implementation of geographic information
metadata could vary based on the interpretation of metadata producers. In an attempt to facilitate the
standardization of implementations, this comprehensive metadata implementation specification provides a
definitive, rule-based encoding for applying ISO 19115. This Technical Specification provides Extensible
Markup Language (XML) schemas that are meant to enhance interoperability by providing a common
specification for describing, validating and exchanging metadata about geographic datasets, dataset series,
individual geographic features, feature attributes, feature types, feature properties, etc.
ISO 19115 defines general-purpose metadata in the field of geographic information. More detailed metadata
for geographic data types and geographic services are defined in other ISO 19100 series standards and user
extensions (ISO 19115). This Technical Specification is also intended to define implementation guidelines for
general-purpose metadata. Where necessary, interpretations of some other ISO 19100 series standards are
incorporated.
ISO 19118 describes the requirements for creating encoding rules based on UML schemas and the
XML-based encoding rules as well as providing an introduction to XML. This Technical Specification utilizes
the encoding rules defined in ISO 19118 and provides the specific details of their application with regard to
deriving XML schema for the UML models in ISO 19115.

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TECHNICAL SPECIFICATION ISO/TS 19139:2007(E)

Geographic information — Metadata — XML schema
implementation
1 Scope
This Technical Specification defines Geographic MetaData XML (gmd) encoding, an XML schema
implementation derived from ISO 19115.
2 Conformance
Conformance with this Technical Specification shall be checked using all the relevant tests specified in
Annex A. The framework, concepts, and methodology for testing, and the criteria to be achieved to claim
conformance are specified in ISO 19105.
3 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 639-2, Codes for the representation of names of languages ― Part 2: Alpha-3 code
ISO 3166 (all parts), Codes for the representation of names of countries and their subdivisions
ISO 8601, Data elements and interchange formats — Information interchange — Representation of dates and
times
ISO/IEC 10646, Information technology ― Universal Multiple-Octet Coded Character Set (UCS)
ISO/TS 19103, Geographic information ― Conceptual schema language
ISO 19105, Geographic information — Conformance and testing
ISO 19107, Geographic information ― Spatial schema
ISO 19108, Geographic information ― Temporal schema
ISO 19109, Geographic information ― Rules for application schema
ISO 19110, Geographic information ― Methodology for feature cataloguing
1)
ISO 19111:― , Geographic information ― Spatial referencing by coordinates
ISO 19115:2003, Geographic information ― Metadata

1) To be published. (Revision of ISO 19111:2003)
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ISO/TS 19139:2007(E)
ISO 19115:2003/Cor. 1:2006, Geographic information ― Metadata ― Technical Corrigendum 1
ISO 19117, Geographic information — Portrayal
ISO 19118:2005, Geographic information ― Encoding
2)
ISO 19136:― , Geographic information ― Geography Markup Language (GML)
W3C XMLName, Namespaces in XML. W3C Recommendation (14 January 1999)
W3C XMLSchema-1, XML Schema Part 1: Structures. W3C Recommendation (2 May 2001)
W3C XMLSchema-2, XML Schema Part 2: Datatypes. W3C Recommendation (2 May 2001)
W3C XML, Extensible Markup Language (XML) 1.0 (Second Edition), W3C Recommendation
(6 October 2000)
W3C XLink, XML Linking Language (XLink) Version 1.0. W3C Recommendation (27 June 2001)
4 Terms and definitions
For the purposes of this Technical Specification, the following terms and definitions apply.
4.1
namespace
collection of names, identified by a URI reference, that are used in XML documents as element names and
attribute names
[W3C XML]
4.2
package
general purpose mechanism for organizing elements into groups
[ISO/TS 19103, definition 4.2.22]
EXAMPLE Identification information; Metadata entity set information; Constraint information.
4.3
realization
semantic relationship between classifiers, wherein one classifier specifies a contract that another classifier
guarantees to carry out
[Booch 1999]
4.4
polymorphism
characteristic of being able to assign a different meaning or usage to something in different contexts –
specifically, to allow an entity such as a variable, a function, or an object to have more than one form
NOTE There are several different kinds of polymorphism.
[http://searchsmallbizit.techtarget.com]

2) To be published.
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ISO/TS 19139:2007(E)
5 Symbols and abbreviated terms
5.1 Acronyms
UML Unified Modelling Language
XCT XML Class Type
XCPT XML Class Property Type
XCGE XML Class Global Element
XML Extensible Markup Language
XPath XML Path Language
XSD XML Schema Definition
XSL Extensible Style Language
XSLT XSL Transformation
5.2 Namespace abbreviations
In the lists below, the item on the left describes the common namespace prefix used to describe the elements
in the namespace. The second item is an English description of the namespace prefix, and the item in
parenthesis is the URI of the actual namespace. These URIs do not correspond necessarily to an effective
location of the schemas.
This first list corresponds to the namespaces defined by this Technical Specification.
gco Geographic Common extensible markup language (http://www.isotc211.org/2005/gco)
gmd Geographic MetaData extensible markup language (http://www.isotc211.org/2005/gmd)
gmx Geographic Metadata XML Schema (http://www.isotc211.org/2005/gmx)
gss Geographic Spatial Schema extensible markup (http://www.isotc211.org/2005/gss)
language
gsr Geographic Spatial Referencing extensible markup (http://www.isotc211.org/2005/gsr)
language
gts Geographic Temporal Schema extensible markup (http://www.isotc211.org/2005/gts)
language
This second list corresponds to external namespaces used by this Technical Specification.
gml Geography Markup Language (use the GML namespace URI stated in
ISO 19136)
xlink XML Linking Language (use the XLINK namespace URI stated in the
W3C XLink recommendation)
xs W3C XML base schemas (use the XML schema namespace URI stated in
the W3C XMLSchema-1 and
W3C XMLSchema-2 recommendations)
5.3 UML model relationships
The diagrams that appear in this Technical Specification are presented using the Unified Modelling Language
(UML) as the conceptual schema language as defined in ISO/TS 19103. ISO 19115:2003, Figure 2, also
displays the UML notation that is used to describe the metadata. In addition to the UML described in
ISO/TS 19103 and shown in ISO 19115, this Technical Specification uses the notation shown in Figure 1.
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ISO/TS 19139:2007(E)

Figure 1 — UML Notation for Realization
The class that is the source of the connection (shown on the left in Figure 1) is guaranteed to carry out (or
implement) the specification of the class at the destination of the connection (shown on the right in Figure 1).
5.4 UML model stereotypes
A UML stereotype is an extension mechanism for existing UML concepts (see ISO 19115). In addition to the
stereotypes already defined in ISO 19115 for describing metadata, this Technical Specification defines
stereotypes necessary for a rules-based encoding into XML schema.
The elements of the UML diagrams depicted in Clause 9 can carry stereotypes specifying an XML
implementation. Those stereotypes are carried by classes representing XML elements or XML types, UML
attributes, UML links (realizations or dependencies) and UML packages.
In this Technical Specification the following stereotypes of classes are used.
a) <>: the class represents an implementation type encoded as an XML choice block. Each
property of the class is implemented as an element of the choice.
b) <>: the class represents an implementation type encoded as an XML complex type.
c) <>: the class represents an XML global element.
d) <>: the class represents an implementation type encoded as an XML simple type.
e) <>: the class represents an implementation type encoded as an XML complex type
with simple content.
In this Technical Specification the following stereotypes of attributes are used.
f) <>: the property is encoded as an XML attribute.
g) <>: the property is encoded as an XML element with a name and a type ( name=”propertyName” type=”propertyType”/>)
h) <>: this stereotype only applies to XML simple types derived from built-in XML types. A property
with the stereotype <> restricts the range of a built-in simple type.
i) <>: the property is encoded as a reference to an XML global element ( ref=”XCGE”/>).
In this Technical Specification the following stereotypes of links are used.
j) <>: (carried by realization relationships). The XCT of the abstract concept to implement is
substituted by the specified external implementation.
k) <>: (carried by realization relationships). The XCGE of the abstract concept to implement is
substituted by the specified external implementation.
l) <>: (carried by realization relationships). The XCPT of the abstract concept to implement is
substituted by the specified external implementation.
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ISO/TS 19139:2007(E)
m) <>: (carried by dependency relationships). The source represents an XML schema
implementing the abstract concepts defined in the target.
n) <>: (carried by dependency relationships). The source and the target represent XML schemas.
The source includes () the target.
o) <>: (carried by dependency relationships). The source and the target represent sets of XML
objects grouped within the same namespace. The source imports () the target.
In this Technical Specification the following stereotypes of packages are used.
p) <>: The package represents an XML schema.
q) <>: The package represents a set of XML objects grouped within the same
namespace.
6 Requirements
6.1 Introduction to gmd
Geographic metadata is represented in ISO 19115 as a set of UML packages containing one or more UML
classes. ISO 19115 provides a universal, encoding-independent view of geographic information metadata.
This Technical Specification provides a universal implementation of ISO 19115 through an XML schema
encoding that conforms to the rules described in ISO 19118.
While the details of XML namespaces are not included in this Technical Specification, the contents of several
namespaces are defined here. A namespace is really a collection of names which can be used in XML
documents as element or attribute names. The namespace is used to identify the names with a particular
schema. A namespace is a URI, and the ones utilized in this Technical Specification are listed in 5.2. A URI is
often cumbersome for reading, writing and including in human discussion, so this Technical Specification will
more often refer to common namespace prefixes when identifying particulars about the contents of a
namespace. The primary namespace defined in this Technical Specification is
http://www.isotc211.org/2005/gmd and the namespace prefix is gmd which stands for Geographic MetaData
extensible markup language.
XML schema offers many alternatives for structuring information for exchange. ISO 19118 defines a set of
encoding rules for transforming a UML conceptual schema from the ISO 19100 series of documents into an
XML schema. Even within the pared down limitations of ISO 19118, there are still choices for the creation of
specific XML schemas. Clauses 7, 8 and 9 describe the details of encoding the ISO 19115 UML conceptual
schema and the UML models depicted in the respective ISO 19100 series of International Standards listed in
Clause 3, into a set of XML schemas. A description of geographic ISO/TS 19139 XML resources and
examples of metadata instance documents are included in Annexes C and D.
Before delving into the details of the encoding it is important to understand why certain encoding rules are
utilized in the development of gmd. Gaining an understanding of the rules will make the capabilities, limitations
and best-practice use of gmd clear. Some of the major goals for gmd were interoperability with other
ISO 19100 series specifications, predictability, extensibility and usability. Further details of these goals are
described in 6.2 to 6.8.
6.2 Rule-based
This XML schema implementation is a rule-based encoding built from the UML models in the ISO 19100
series of International Standards as required by ISO 19118. Using this methodology achieves a couple of the
goals mentioned in 6.1. First, the resulting gmd schemas are based directly on other ISO 19100 series
International Standards and therefore increase the chance for interoperability. Second, the resulting schema is
predictable since any class, attribute, association, etc. is encoded just as other UML elements of the same
type are encoded.
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ISO/TS 19139:2007(E)
Although not discussed in detail in this Technical Specification, having a rule-based encoding also allows the
XML schemas to be generated in an automated or semi-automated fashion.
6.3 Quality
Quality in terms of the XML schema implementation implies simple XML schemas as well as the human
readability of the XML files. The structural complexity of the ISO 19100 series, particularly ISO 19115, implies
that it is not possible to provide simple XML schemas for geographic metadata. But the encoding rules are
defined so that a user can directly create and/or understand the content of an XML instance document using
the UML models in ISO 19115 as a basis. Additionally, an implementer can determine the XML schema
implementation of the UML models in ISO 19115 by knowing the encoding rules.
Another aspect to the quality of gmd is completeness. This Technical Specification encodes the entire UML
model from ISO 19115 without regard to a particular usage for gmd or a particular application schema that will
utilize gmd.
6.4 Web implementations
One of the goals stated in 6.1 is usability. Usability, as it pertains to the design of gmd, focuses on the
exchange of geographic metadata with the understanding that this will often happen in a web-like
environment. While there is no restraint against creating geographic metadata instance documents based on
gmd which never transfer across a network, there are many aspects to the design that are intended to aid
internet and web-like transfer of data.
6.5 Use of external XML implementations
Another design principle that aids interoperability and usability is the use of existing XML schemas. If an XML
schema standard already exists that encodes a part of the ISO 19100 series pertaining to geographic
metadata then it is advantageous to incorporate that XML schema standard into gmd. If gmd uses the external
XML schema directly, then interoperability is enhanced. It is also likely that software already exists that can
process instance documents that conform to the external XML. Furthermore, if the external schema is well
designed it might be more efficient than XML schema generated from a series of encoding rules and this
might help achieve the goal of usability.
While using an implementation that already exists has some important advantages, the external XML
schemas should not violate the primary design principles of gmd. For example, if an external XML schema
implements part of the ISO 19100 series but does so in a cumbersome, unusable manner then it is not
incorporated into gmd. Additionally, if an external XML schema does not readily meet the requirements stated
in 6.6 for multilingual support then it is not incorporated into gmd.
6.6 Multilingual support
Cultural and linguistic adaptability is a basic requirement for any textual metadata elements. In Annex J of
ISO 19115:2003, there is an informative discussion of multilingual textual metadata elements. In order to
enhance the chances for interoperability of implementations it is important that a normative mechanism for
multilingual support be included in this Technical Specification. The details of multilingual support are
described in 7.3 and 9.8.6 but for the sake of understanding the design of gmd it is important to understand
that special consideration is given to this requirement. The specific mechanisms used to achieve this goal are
polymorphism and codelist registers. Polymorphism is introduced in 6.7 and codelist registers are described in
7.4.4.4.
It is also important to understand that the multilingual support that exists in W3C XML is not sufficient for the
expression of geographic metadata. In W3C XML, “A special attribute named xml
...