ISO 19108:2002
(Main)Geographic information — Temporal schema
Geographic information — Temporal schema
ISO 19108:2002 defines concepts for describing temporal characteristics of geographic information. It depends upon existing information technology standards for the interchange of temporal information. It provides a basis for defining temporal feature attributes, feature operations, and feature associations, and for defining the temporal aspects of metadata about geographic information. Since this International Standard is concerned with the temporal characteristics of geographic information as they are abstracted from the real world, it emphasizes valid time rather than transaction time.
Information géographique — Schéma temporel
Geografske informacije - Časovna shema
General Information
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 19108
First edition
2002-09-01
Geographic information — Temporal
schema
Information géographique — Schéma temporel
Reference number
ISO 19108:2002(E)
©
ISO 2002
---------------------- Page: 1 ----------------------
ISO 19108:2002(E)
PDF disclaimer
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Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters
were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event
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© ISO 2002
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.ch
Web www.iso.ch
Printed in Switzerland
ii © ISO 2002 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 19108:2002(E)
Contents Page
Foreword . v
Introduction. vi
1 Scope. 1
2 Conformance. 1
2.1 Conformance classes and requirements. 1
2.2 Application schemas for data transfer. 1
2.3 Application schemas for data with operations . 1
2.4 Feature catalogues. 1
2.5 Metadata element specifications . 1
2.6 Metadata for data sets . 1
3 Normative references. 1
4 Terms, definitions and abbreviated terms. 2
4.1 Terms and definitions. 2
4.2 Abbreviated terms. 6
5 Conceptual schema for temporal aspects of geographic information. 6
5.1 Structure of the schema . 6
5.2 Geometry of time. 7
5.2.1 Time as a dimension. 7
5.2.2 Temporal objects. 7
5.2.3 Temporal geometric primitives. 8
5.2.4 Temporal topological objects . 13
5.3 Temporal reference systems . 16
5.3.1 Types of temporal reference systems. 16
5.3.2 Calendars and clocks. 17
5.3.3 Temporal coordinate systems. 19
5.3.4 Ordinal temporal reference systems. 20
5.4 Temporal position. 21
5.4.1 Introduction. 21
5.4.2 TM_Position. 21
5.4.3 TM_TemporalPosition. 21
5.4.4 Position referenced to calendar and clock. 23
5.4.5 Position referenced to a temporal coordinate system. 23
5.4.6 Position referenced to an ordinal temporal reference system.24
5.5 Time and components of geographic information . 24
5.5.1 Temporal aspects of geographic information components . 24
5.5.2 Temporal feature attributes. 25
5.5.3 Temporal feature operations. 26
5.5.4 Time and feature associations. 27
5.5.5 Temporal metadata elements. 29
Annex A (normative) Abstract test suite . 31
A.1 Application schemas for data transfer. 31
A.2 Application schemas for data with operations . 31
A.3 Feature catalogues. 31
A.4 Metadata element specifications . 32
A.5 Metadata for data sets . 32
Annex B (informative) Use of time in application schemas . 33
B.1 Temporal feature attributes. 33
B.1.1 TM_GeometricPrimitive as a data type . 33
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ISO 19108:2002(E)
B.1.2 TM_GeometricPrimitive as a temporal attribute . 33
B.1.3 TM_TopologicalComplex as an attribute . 34
B.1.4 Recurring attribute values. 34
B.2 Temporal feature associations. 35
B.2.1 Simple temporal associations. 35
B.2.2 Feature succession. 36
B.3 Feature associations with temporal characteristics. 37
Annex C (normative) Describing temporal reference systems in metadata. 38
C.1 Metadata for temporal reference systems . 38
Annex D (informative) Description of calendars. 41
D.1 Internal structure of calendars. 41
D.2 Describing a calendar. 42
D.3 Examples. 43
D.3.1 Julian calendar. 43
D.3.2 Modern Japanese calendar . 44
D.3.3 Ancient Babylonian calendar . 45
D.3.4 Global Positioning System calendar. 47
Bibliography. 48
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ISO 19108:2002(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 3.
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 International Standard may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 19108 was prepared by Technical Committee ISO/TC 211, Geographic information/Geomatics.
Annexes A and C form a normative part of this International Standard. Annexes B and D are for information only.
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ISO 19108:2002(E)
Introduction
This International Standard defines the standard concepts needed to describe the temporal characteristics of
geographic information as they are abstracted from the real world. Temporal characteristics of geographic
information include feature attributes, feature operations, feature associations, and metadata elements that take a
value in the temporal domain.
The widespread application of computers and geographic information systems has led to the increased analysis of
geospatial data within multiple disciplines. Geographic information is not confined to a three-dimensional spatial
domain. Many geographic information systems require data with temporal characteristics. A standardized
conceptual schema for temporal characteristics will increase the ability of geographic information to be used for
certain types of applications such as simulations and predictive modelling.
As a fundamental physical reality, time is of interest to the whole range of scientific and technical disciplines. Many
of the concepts described in this International Standard are applicable outside of the field of geographic
information. ISO/TC 211 does not intend to develop independent standards for the description of time, but the
technical committee believes that it is necessary to standardize the way to describe the temporal characteristics of
geographic data sets and features. Geographic information system and software developers and users of
geographic information will use this schema to provide consistently understandable temporal data structures.
Historically, temporal characteristics of features have been treated as thematic feature attributes. For example, a
feature "Building" may have an attribute "date of construction". However, there is increasing interest in describing
the behaviour of features as a function of time. This can be supported to a limited extent when time is treated
independently of space. For example, the path followed by a moving object can be represented as a set of features
called "way point", each of which is represented as a point and has an attribute that provides the time at which the
object was at that spatial position. Behaviour in time may be described more easily if the temporal dimension is
combined with the spatial dimensions, so that a feature can be represented as a spatiotemporal object. For
example, the path of a moving object could be represented as a curve described by coordinates in x, y and t. This
International Standard has been prepared in order to standardize the use of time in feature attributes. Although it
does not describe feature geometry in terms of a combination of spatial and temporal coordinates, it has been
written to establish a basis for doing so in a future standard within the ISO 19100 series.
vi © ISO 2002 – All rights reserved
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INTERNATIONAL STANDARD ISO 19108:2002(E)
Geographic information — Temporal schema
1 Scope
This International Standard defines concepts for describing temporal characteristics of geographic information. It
depends upon existing information technology standards for the interchange of temporal information. It provides a
basis for defining temporal feature attributes, feature operations, and feature associations, and for defining the
temporal aspects of metadata about geographic information. Since this International Standard is concerned with
the temporal characteristics of geographic information as they are abstracted from the real world, it emphasizes
valid time rather than transaction time.
2 Conformance
2.1 Conformance classes and requirements
This International Standard defines five conformance classes, which depend upon the nature of the test item.
2.2 Application schemas for data transfer
To conform to this International Standard, an application schema for data transfer shall satisfy the requirements of
A.1 of the Abstract Test Suite in annex A.
2.3 Application schemas for data with operations
To conform to this International Standard, an application schema that supports operations on data shall satisfy the
requirements of A.2 of the Abstract Test Suite in annex A.
2.4 Feature catalogues
To conform to this International Standard, a feature catalogue shall satisfy the requirements of A.3 of the Abstract
Test Suite in annex A.
2.5 Metadata element specifications
To conform to this International Standard, a metadata specification shall satisfy the requirements of A.4 of the
Abstract Test Suite in annex A.
2.6 Metadata for data sets
To conform to this International Standard, metadata for a data set shall satisfy the requirements of A.5 of the
Abstract Test Suite in annex A.
3 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this International Standard. For dated references, subsequent amendments to, or revisions of, any of these
© ISO 2002 – All rights reserved 1
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ISO 19108:2002(E)
publications do not apply. However, parties to agreements based on this International Standard are encouraged to
investigate the possibility of applying the most recent editions of the normative documents indicated below. For
undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC
maintain registers of currently valid International Standards.
ISO 31-1:1992, Quantities and units — Part 1: Space and time
ISO 1000:1992, SI units and recommendations for the use of their multiples and of certain other units
ISO 8601:2000, Data elements and interchange formats ― Information interchange ― Representation of dates and
times
ISO/IEC 11404:1996, Information technology ― Programming languages, their environments and system software
interfaces ― Language-independent data types
1)
ISO/TS 19103: , Geographic information — Conceptual schema language
1)
ISO 19107: , Geographic information — Spatial schema
1)
ISO 19109: , Geographic information — Rules for application schema
1)
ISO 19110: , Geographic information — Methodology for feature cataloguing
1)
ISO 19111: , Geographic information — Spatial referencing by coordinates
1)
ISO 19115: , Geographic information — Metadata
4 Terms, definitions and abbreviated terms
4.1 Terms and definitions
For the purposes of this International Standard, the following terms and definitions apply.
4.1.1
calendar
discrete temporal reference system that provides a basis for defining temporal position to a resolution of one
day
4.1.2
calendar era
sequence of periods of one of the types used in a calendar, counted from a specified event
4.1.3
UTC
Coordinated Universal Time
time scale maintained by the Bureau International des Poids et Mesures (International Bureau of Weights and
Measures) and the International Earth Rotation Service (IERS) that forms the basis of a coordinated dissemination
of standard frequencies and time signals [ITU-R Rec.TF.686-1 (1997)]
4.1.4
day
period having a duration nominally equivalent to the periodic time of the Earth's rotation around its axis
1) To be published.
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ISO 19108:2002(E)
4.1.5
edge
one-dimensional topological primitive [ISO 19107]
NOTE The geometric realization of an edge is a curve. The boundary of an edge is the set of one or two nodes associated
to the edge within a topological complex.
4.1.6
event
action which occurs at an instant
4.1.7
feature
abstraction of real world phenomena [ISO 19101]
NOTE A feature may occur as a type or an instance. Feature type or feature instance should be used when only one is
meant.
4.1.8
feature association
relationship between features [ISO 19109]
NOTE 1 A feature association may occur as a type or an instance. Feature association type or feature association instance
is used when only one is meant.
NOTE 2 Feature associations include aggregation of features.
4.1.9
feature attribute
characteristic of a feature [Adapted from ISO 19110]
NOTE A feature attribute has a name, a data type, and a value domain associated to it.
4.1.10
feature division
feature succession in which a previously existing feature is replaced by two or more distinct feature instances of
the same feature type
EXAMPLE An instance of the feature type “land parcel” is replaced by two instances of the same type when the parcel is
legally subdivided.
4.1.11
feature fusion
feature succession in which two or more previously existing instances of a feature type are replaced by a single
instance of the same feature type
EXAMPLE Two instances of the feature type “pasture” are replaced by a single instance when the fence between the
pastures is removed.
4.1.12
feature operation
operation that every instance of a feature type may perform [ISO 19110]
EXAMPLE An operation upon a “dam” is to raise the dam. The results of this operation are to raise the height of the “dam”
and the level of water in a “reservoir”.
NOTE Feature operations provide a basis for feature type definition.
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ISO 19108:2002(E)
4.1.13
feature substitution
feature succession in which one feature instance is replaced by another feature instance of the same or different
feature type
EXAMPLE An instance of feature type “building” is razed and replaced by an instance of feature type “parking lot”.
4.1.14
feature succession
replacement of one or more feature instances by other feature instances, such that the first feature instances
cease to exist
4.1.15
geometric primitive
object representing a single, connected, homogeneous element of space [ISO 19107]
NOTE Geometric primitives are non-decomposed objects that present information about geometric configuration. They
include points, curves, surfaces, and solids.
4.1.16
Gregorian calendar
calendar in general use; first introduced in 1582 to define a year that more closely approximated the tropical year
than the Julian calendar [adapted from ISO 8601:2000]
NOTE 1 The introduction of the Gregorian calendar included the cancellation of the accumulated inaccuracies of the Julian
year. In the Gregorian calendar, a calendar year is either a common year or a leap year; each year is divided into 12 sequential
months.
4.1.17
instant
0-dimensional geometric primitive representing position in time
NOTE The geometry of time is discussed in 5.2.
4.1.18
interval scale
scale with an arbitrary origin which can be used to describe both ordering of values and distances between values
NOTE Ratios of values measured on an interval scale have no meaning.
4.1.19
Julian date
Julian day number followed by the decimal fraction of the day elapsed since the preceding noon
4.1.20
Julian day number
number of days elapsed since Greenwich mean noon on 1 January 4713 BC, Julian proleptic calendar
4.1.21
life span
period during which something exists
NOTE Valid-time life span is the period during which an object exists in the modelled reality. Transaction-time life span is
the period during which a database object is current in the database.
4.1.22
month
period approximately equal in duration to the periodic time of a lunar cycle
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ISO 19108:2002(E)
NOTE The duration of a month is an integer number of days. The number of days in a month is determined by the rules of
the particular calendar.
4.1.23
node
0-dimensional topological primitive [ISO 19107]
NOTE The boundary of a node is the empty set.
4.1.24
ordinal era
one of a set of named periods ordered in time
4.1.25
ordinal scale
scale which provides a basis for measuring only the relative position of an object
4.1.26
ordinal temporal reference system
temporal reference system composed of ordinal eras
4.1.27
period
one-dimensional geometric primitive representing extent in time
NOTE A period is bounded by two different temporal positions.
4.1.28
periodic time
duration of one cycle [adapted from ISO 31-2:1992]
4.1.29
point
0-dimensional geometric primitive, representing a position [ISO 19107]
NOTE The boundary of a point is the empty set.
4.1.30
temporal coordinate
distance from the origin of the interval scale used as the basis for a temporal coordinate system
4.1.31
temporal coordinate system
temporal reference system based on an interval scale on which distance is measured as a multiple of a single
unit of time
4.1.32
temporal feature association
feature association characterized by a reference to time or to a temporal constraint
4.1.33
temporal feature operation
feature operation specified as a function of time
4.1.34
temporal position
location relative to a temporal reference system
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ISO 19108:2002(E)
4.1.35
temporal reference system
reference system against which time is measured
4.1.36
topological complex
collection of topological primitives that is closed under the boundary operations [ISO 19107]
NOTE Closed under the boundary operations means that if a topological primitive is in the topological complex, then its
boundary objects are also in the topological complex.
4.1.37
topological primitive
topological object that represents a single, non-decomposable element [ISO 19107]
NOTE A topological primitive corresponds to the interior of a geometric primitive of the same dimension in a geometric
realization.
4.1.38
transaction time
time when a fact is current in a database and may be retrieved [Jensen et al. (1994)]
4.1.39
valid time
time when a fact is true in the abstracted reality [Jensen et al. (1994)]
4.2 Abbreviated terms
For the purposes of this International Standard, the following abbreviations apply.
AD Anno Domini
BC Before Christ
GPS Global Positioning System
TOW Time of Week
UML Unified Modeling Language
UTC Coordinated Universal Time
WN Week Number
5 Conceptual schema for temporal aspects of geographic information
5.1 Structure of the schema
This clause presents a conceptual schema for describing temporal aspects of geographic information. The schema
is specified in the Unified Modeling Language (UML) [Object Management Group (1999)]. ISO/TS 19103 describes
the way in which UML is used in this family of standards. The three primary aspects of a UML class are attributes,
operations, and associations. This schema uses all three. This schema is an abstract model; to conform to this
International Standard, an implementation shall provide the capabilities described by these elements of the abstract
model, but it need not implement them in the same way.
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ISO 19108:2002(E)
The schema consists of two packages (see Figure 1). The package Temporal Objects (described in 5.2) defines
temporal geometric and topological objects that shall be used as values for the temporal characteristics of features
and data sets. The temporal position of an object shall be specified in relation to a temporal reference system. The
package Temporal Reference System (5.3, 5.4) provides elements for describing temporal reference systems.
Subclause 5.5 describes how the concepts specified in 5.2 through 5.4 shall be used in the context of geographic
information.
Figure 1 — Structure of the temporal schema
Names of UML classes defined in the ISO 19100 series of standards begin with a two-letter prefix followed by an
underscore to identify the specific standard, and possibly the package, in which they are defined. TM_ is used to
identify classes defined in this International Standard.
5.2 Geometry of time
5.2.1 Time as a dimension
Time is a dimension analogous to any of the spatial dimensions. Like space, time has geom
...
SLOVENSKI STANDARD
SIST ISO 19108:2003
01-november-2003
*HRJUDIVNHLQIRUPDFLMHýDVRYQDVKHPD
Geographic information -- Temporal schema
Information géographique -- Schéma temporel
Ta slovenski standard je istoveten z: ISO 19108:2002
ICS:
07.040 Astronomija. Geodezija. Astronomy. Geodesy.
Geografija Geography
35.240.70 Uporabniške rešitve IT v IT applications in science
znanosti
SIST ISO 19108:2003 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST ISO 19108:2003
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SIST ISO 19108:2003
INTERNATIONAL ISO
STANDARD 19108
First edition
2002-09-01
Geographic information — Temporal
schema
Information géographique — Schéma temporel
Reference number
ISO 19108:2002(E)
©
ISO 2002
---------------------- Page: 3 ----------------------
SIST ISO 19108:2003
ISO 19108:2002(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall not
be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In downloading this
file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat accepts no liability in this
area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters
were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event
that a problem relating to it is found, please inform the Central Secretariat at the address given below.
© ISO 2002
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.ch
Web www.iso.ch
Printed in Switzerland
ii © ISO 2002 – All rights reserved
---------------------- Page: 4 ----------------------
SIST ISO 19108:2003
ISO 19108:2002(E)
Contents Page
Foreword . v
Introduction. vi
1 Scope. 1
2 Conformance. 1
2.1 Conformance classes and requirements. 1
2.2 Application schemas for data transfer. 1
2.3 Application schemas for data with operations . 1
2.4 Feature catalogues. 1
2.5 Metadata element specifications . 1
2.6 Metadata for data sets . 1
3 Normative references. 1
4 Terms, definitions and abbreviated terms. 2
4.1 Terms and definitions. 2
4.2 Abbreviated terms. 6
5 Conceptual schema for temporal aspects of geographic information. 6
5.1 Structure of the schema . 6
5.2 Geometry of time. 7
5.2.1 Time as a dimension. 7
5.2.2 Temporal objects. 7
5.2.3 Temporal geometric primitives. 8
5.2.4 Temporal topological objects . 13
5.3 Temporal reference systems . 16
5.3.1 Types of temporal reference systems. 16
5.3.2 Calendars and clocks. 17
5.3.3 Temporal coordinate systems. 19
5.3.4 Ordinal temporal reference systems. 20
5.4 Temporal position. 21
5.4.1 Introduction. 21
5.4.2 TM_Position. 21
5.4.3 TM_TemporalPosition. 21
5.4.4 Position referenced to calendar and clock. 23
5.4.5 Position referenced to a temporal coordinate system. 23
5.4.6 Position referenced to an ordinal temporal reference system.24
5.5 Time and components of geographic information . 24
5.5.1 Temporal aspects of geographic information components . 24
5.5.2 Temporal feature attributes. 25
5.5.3 Temporal feature operations. 26
5.5.4 Time and feature associations. 27
5.5.5 Temporal metadata elements. 29
Annex A (normative) Abstract test suite . 31
A.1 Application schemas for data transfer. 31
A.2 Application schemas for data with operations . 31
A.3 Feature catalogues. 31
A.4 Metadata element specifications . 32
A.5 Metadata for data sets . 32
Annex B (informative) Use of time in application schemas . 33
B.1 Temporal feature attributes. 33
B.1.1 TM_GeometricPrimitive as a data type . 33
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SIST ISO 19108:2003
ISO 19108:2002(E)
B.1.2 TM_GeometricPrimitive as a temporal attribute . 33
B.1.3 TM_TopologicalComplex as an attribute . 34
B.1.4 Recurring attribute values. 34
B.2 Temporal feature associations. 35
B.2.1 Simple temporal associations. 35
B.2.2 Feature succession. 36
B.3 Feature associations with temporal characteristics. 37
Annex C (normative) Describing temporal reference systems in metadata. 38
C.1 Metadata for temporal reference systems . 38
Annex D (informative) Description of calendars. 41
D.1 Internal structure of calendars. 41
D.2 Describing a calendar. 42
D.3 Examples. 43
D.3.1 Julian calendar. 43
D.3.2 Modern Japanese calendar . 44
D.3.3 Ancient Babylonian calendar . 45
D.3.4 Global Positioning System calendar. 47
Bibliography. 48
iv © ISO 2002 – All rights reserved
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SIST ISO 19108:2003
ISO 19108:2002(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 3.
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 International Standard may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 19108 was prepared by Technical Committee ISO/TC 211, Geographic information/Geomatics.
Annexes A and C form a normative part of this International Standard. Annexes B and D are for information only.
© ISO 2002 – All rights reserved v
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SIST ISO 19108:2003
ISO 19108:2002(E)
Introduction
This International Standard defines the standard concepts needed to describe the temporal characteristics of
geographic information as they are abstracted from the real world. Temporal characteristics of geographic
information include feature attributes, feature operations, feature associations, and metadata elements that take a
value in the temporal domain.
The widespread application of computers and geographic information systems has led to the increased analysis of
geospatial data within multiple disciplines. Geographic information is not confined to a three-dimensional spatial
domain. Many geographic information systems require data with temporal characteristics. A standardized
conceptual schema for temporal characteristics will increase the ability of geographic information to be used for
certain types of applications such as simulations and predictive modelling.
As a fundamental physical reality, time is of interest to the whole range of scientific and technical disciplines. Many
of the concepts described in this International Standard are applicable outside of the field of geographic
information. ISO/TC 211 does not intend to develop independent standards for the description of time, but the
technical committee believes that it is necessary to standardize the way to describe the temporal characteristics of
geographic data sets and features. Geographic information system and software developers and users of
geographic information will use this schema to provide consistently understandable temporal data structures.
Historically, temporal characteristics of features have been treated as thematic feature attributes. For example, a
feature "Building" may have an attribute "date of construction". However, there is increasing interest in describing
the behaviour of features as a function of time. This can be supported to a limited extent when time is treated
independently of space. For example, the path followed by a moving object can be represented as a set of features
called "way point", each of which is represented as a point and has an attribute that provides the time at which the
object was at that spatial position. Behaviour in time may be described more easily if the temporal dimension is
combined with the spatial dimensions, so that a feature can be represented as a spatiotemporal object. For
example, the path of a moving object could be represented as a curve described by coordinates in x, y and t. This
International Standard has been prepared in order to standardize the use of time in feature attributes. Although it
does not describe feature geometry in terms of a combination of spatial and temporal coordinates, it has been
written to establish a basis for doing so in a future standard within the ISO 19100 series.
vi © ISO 2002 – All rights reserved
---------------------- Page: 8 ----------------------
SIST ISO 19108:2003
INTERNATIONAL STANDARD ISO 19108:2002(E)
Geographic information — Temporal schema
1 Scope
This International Standard defines concepts for describing temporal characteristics of geographic information. It
depends upon existing information technology standards for the interchange of temporal information. It provides a
basis for defining temporal feature attributes, feature operations, and feature associations, and for defining the
temporal aspects of metadata about geographic information. Since this International Standard is concerned with
the temporal characteristics of geographic information as they are abstracted from the real world, it emphasizes
valid time rather than transaction time.
2 Conformance
2.1 Conformance classes and requirements
This International Standard defines five conformance classes, which depend upon the nature of the test item.
2.2 Application schemas for data transfer
To conform to this International Standard, an application schema for data transfer shall satisfy the requirements of
A.1 of the Abstract Test Suite in annex A.
2.3 Application schemas for data with operations
To conform to this International Standard, an application schema that supports operations on data shall satisfy the
requirements of A.2 of the Abstract Test Suite in annex A.
2.4 Feature catalogues
To conform to this International Standard, a feature catalogue shall satisfy the requirements of A.3 of the Abstract
Test Suite in annex A.
2.5 Metadata element specifications
To conform to this International Standard, a metadata specification shall satisfy the requirements of A.4 of the
Abstract Test Suite in annex A.
2.6 Metadata for data sets
To conform to this International Standard, metadata for a data set shall satisfy the requirements of A.5 of the
Abstract Test Suite in annex A.
3 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this International Standard. For dated references, subsequent amendments to, or revisions of, any of these
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publications do not apply. However, parties to agreements based on this International Standard are encouraged to
investigate the possibility of applying the most recent editions of the normative documents indicated below. For
undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC
maintain registers of currently valid International Standards.
ISO 31-1:1992, Quantities and units — Part 1: Space and time
ISO 1000:1992, SI units and recommendations for the use of their multiples and of certain other units
ISO 8601:2000, Data elements and interchange formats ― Information interchange ― Representation of dates and
times
ISO/IEC 11404:1996, Information technology ― Programming languages, their environments and system software
interfaces ― Language-independent data types
1)
ISO/TS 19103: , Geographic information — Conceptual schema language
1)
ISO 19107: , Geographic information — Spatial schema
1)
ISO 19109: , Geographic information — Rules for application schema
1)
ISO 19110: , Geographic information — Methodology for feature cataloguing
1)
ISO 19111: , Geographic information — Spatial referencing by coordinates
1)
ISO 19115: , Geographic information — Metadata
4 Terms, definitions and abbreviated terms
4.1 Terms and definitions
For the purposes of this International Standard, the following terms and definitions apply.
4.1.1
calendar
discrete temporal reference system that provides a basis for defining temporal position to a resolution of one
day
4.1.2
calendar era
sequence of periods of one of the types used in a calendar, counted from a specified event
4.1.3
UTC
Coordinated Universal Time
time scale maintained by the Bureau International des Poids et Mesures (International Bureau of Weights and
Measures) and the International Earth Rotation Service (IERS) that forms the basis of a coordinated dissemination
of standard frequencies and time signals [ITU-R Rec.TF.686-1 (1997)]
4.1.4
day
period having a duration nominally equivalent to the periodic time of the Earth's rotation around its axis
1) To be published.
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4.1.5
edge
one-dimensional topological primitive [ISO 19107]
NOTE The geometric realization of an edge is a curve. The boundary of an edge is the set of one or two nodes associated
to the edge within a topological complex.
4.1.6
event
action which occurs at an instant
4.1.7
feature
abstraction of real world phenomena [ISO 19101]
NOTE A feature may occur as a type or an instance. Feature type or feature instance should be used when only one is
meant.
4.1.8
feature association
relationship between features [ISO 19109]
NOTE 1 A feature association may occur as a type or an instance. Feature association type or feature association instance
is used when only one is meant.
NOTE 2 Feature associations include aggregation of features.
4.1.9
feature attribute
characteristic of a feature [Adapted from ISO 19110]
NOTE A feature attribute has a name, a data type, and a value domain associated to it.
4.1.10
feature division
feature succession in which a previously existing feature is replaced by two or more distinct feature instances of
the same feature type
EXAMPLE An instance of the feature type “land parcel” is replaced by two instances of the same type when the parcel is
legally subdivided.
4.1.11
feature fusion
feature succession in which two or more previously existing instances of a feature type are replaced by a single
instance of the same feature type
EXAMPLE Two instances of the feature type “pasture” are replaced by a single instance when the fence between the
pastures is removed.
4.1.12
feature operation
operation that every instance of a feature type may perform [ISO 19110]
EXAMPLE An operation upon a “dam” is to raise the dam. The results of this operation are to raise the height of the “dam”
and the level of water in a “reservoir”.
NOTE Feature operations provide a basis for feature type definition.
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4.1.13
feature substitution
feature succession in which one feature instance is replaced by another feature instance of the same or different
feature type
EXAMPLE An instance of feature type “building” is razed and replaced by an instance of feature type “parking lot”.
4.1.14
feature succession
replacement of one or more feature instances by other feature instances, such that the first feature instances
cease to exist
4.1.15
geometric primitive
object representing a single, connected, homogeneous element of space [ISO 19107]
NOTE Geometric primitives are non-decomposed objects that present information about geometric configuration. They
include points, curves, surfaces, and solids.
4.1.16
Gregorian calendar
calendar in general use; first introduced in 1582 to define a year that more closely approximated the tropical year
than the Julian calendar [adapted from ISO 8601:2000]
NOTE 1 The introduction of the Gregorian calendar included the cancellation of the accumulated inaccuracies of the Julian
year. In the Gregorian calendar, a calendar year is either a common year or a leap year; each year is divided into 12 sequential
months.
4.1.17
instant
0-dimensional geometric primitive representing position in time
NOTE The geometry of time is discussed in 5.2.
4.1.18
interval scale
scale with an arbitrary origin which can be used to describe both ordering of values and distances between values
NOTE Ratios of values measured on an interval scale have no meaning.
4.1.19
Julian date
Julian day number followed by the decimal fraction of the day elapsed since the preceding noon
4.1.20
Julian day number
number of days elapsed since Greenwich mean noon on 1 January 4713 BC, Julian proleptic calendar
4.1.21
life span
period during which something exists
NOTE Valid-time life span is the period during which an object exists in the modelled reality. Transaction-time life span is
the period during which a database object is current in the database.
4.1.22
month
period approximately equal in duration to the periodic time of a lunar cycle
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NOTE The duration of a month is an integer number of days. The number of days in a month is determined by the rules of
the particular calendar.
4.1.23
node
0-dimensional topological primitive [ISO 19107]
NOTE The boundary of a node is the empty set.
4.1.24
ordinal era
one of a set of named periods ordered in time
4.1.25
ordinal scale
scale which provides a basis for measuring only the relative position of an object
4.1.26
ordinal temporal reference system
temporal reference system composed of ordinal eras
4.1.27
period
one-dimensional geometric primitive representing extent in time
NOTE A period is bounded by two different temporal positions.
4.1.28
periodic time
duration of one cycle [adapted from ISO 31-2:1992]
4.1.29
point
0-dimensional geometric primitive, representing a position [ISO 19107]
NOTE The boundary of a point is the empty set.
4.1.30
temporal coordinate
distance from the origin of the interval scale used as the basis for a temporal coordinate system
4.1.31
temporal coordinate system
temporal reference system based on an interval scale on which distance is measured as a multiple of a single
unit of time
4.1.32
temporal feature association
feature association characterized by a reference to time or to a temporal constraint
4.1.33
temporal feature operation
feature operation specified as a function of time
4.1.34
temporal position
location relative to a temporal reference system
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4.1.35
temporal reference system
reference system against which time is measured
4.1.36
topological complex
collection of topological primitives that is closed under the boundary operations [ISO 19107]
NOTE Closed under the boundary operations means that if a topological primitive is in the topological complex, then its
boundary objects are also in the topological complex.
4.1.37
topological primitive
topological object that represents a single, non-decomposable element [ISO 19107]
NOTE A topological primitive corresponds to the interior of a geometric primitive of the same dimension in a geometric
realization.
4.1.38
transaction time
time when a fact is current in a database and may be retrieved [Jensen et al. (1994)]
4.1.39
valid time
time when a fact is true in the abstracted reality [Jensen et al. (1994)]
4.2 Abbreviated terms
For the purposes of this International Standard, the following abbreviations apply.
AD Anno Domini
BC Before Christ
GPS Global Positioning System
TOW Time of Week
UML Unified Modeling Language
UTC Coordinated Universal Time
WN Week Number
5 Conceptual schema for temporal aspects of geographic information
5.1 Structure of the schema
This clause presents a conceptual schema for describing temporal aspects of geographic information. The schema
is specified in the Unified Modeling Language (UML) [Object Management Group (1999)]. ISO/TS 19103 describes
the way in which UML is used in this family of standards. The three primary aspects of a UML class are attributes,
operations, and associations. This schema uses all three. This schema is an abstract model; to conform to this
International Standard, an implementation shall provide the capabilities described by these elements of the abstract
model, but it need not implement them in the same way.
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The schema consists of two packages (see Figure 1). The package Temporal Objects (described in 5.2) defines
...
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