ISO 17572-1:2022
(Main)Intelligent transport systems (ITS) — Location referencing for geographic databases — Part 1: General requirements and conceptual model
Intelligent transport systems (ITS) — Location referencing for geographic databases — Part 1: General requirements and conceptual model
The ISO 17572 series specifies location referencing methods (LRMs) that describe locations in the context of geographic databases and that are intended for use in locating transport-related phenomena both in an encoder system and from the decoder side. This document defines what is meant by such objects and describes the reference in detail, including whether or not components of the reference are mandatory or optional, and their characteristics. The ISO 17572 series specifies three different LRMs: — pre-coded LRM (pre-coded profile); — dynamic LRM (dynamic profile); — precise relative LRM (precise relative profile). The ISO 17572 series does not define a physical format for implementing the LRM. However, the requirements for physical formats are defined. The ISO 17572 series does not define details of the location referencing system (LRS), i.e. how the LRMs are to be implemented in software, hardware or processes. This document specifies the following general LRM-related subjects: — requirements of an LRM; — conceptual data model for LRMs; — inventory LRMs (see Annex A). This document also provides: — examples of conceptual model use (see Annex B); — a comparison of definitions with ISO/TC 211 (see Annex C).
Systèmes de transport intelligents (ITS) — Localisation pour bases de données géographiques — Partie 1: Exigences générales et modèle conceptuel
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 17572-1
Third edition
2022-07
Intelligent transport systems (ITS) —
Location referencing for geographic
databases —
Part 1:
General requirements and conceptual
model
Systèmes de transport intelligents (ITS) — Localisation pour bases de
données géographiques —
Partie 1: Exigences générales et modèle conceptuel
Reference number
ISO 17572-1:2022(E)
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ISO 17572-1:2022(E)
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ISO 17572-1:2022(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Abbreviated terms . 7
5 Objectives and requirements for a location referencing method .7
5.1 Objectives for an optimal location referencing method . 7
5.2 Requirements of the location referencing method . 8
6 Conceptual data model for location referencing methods . 9
6.1 Role of conceptual model. 9
6.2 Components of conceptual model . 9
6.3 Description of the conceptual model . 10
6.4 Location categories . 10
6.5 Conceptual model of a road network . 11
6.6 Conceptual model of area locations .12
Annex A (informative) Inventory of location referencing methods .14
Annex B (informative) Examples of location referencing methods in use (mapping to
conceptual data model for location referencing systems) .18
Annex C (informative) Comparison of definitions with ISO/TC 211 .20
Bibliography .21
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ISO 17572-1:2022(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
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ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/
iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 204, Intelligent transport systems.
This third edition cancels and replaces second edition (ISO 17572-1:2015), which has been technically
revised.
The main changes are as follows:
— Annex C has been significantly reduced;
— Annex D, Annex E and Annex F have been deleted;
— cross-references have been updated throughout the document to refer to the most recent edition of
the relevant publication;
— various minor editorial modifications have been made throughout.
A list of all parts in the ISO 17572 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
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ISO 17572-1:2022(E)
Introduction
A location reference (LR) is a unique identification of a geographic object. In a digital world, a real-
world geographic object can be represented by a feature in a geographic database. An example of a
commonly known location reference is a postal address of a house. Examples of object instances include
a particular exit ramp on a particular motorway, a road junction or a hotel. For efficiency reasons,
location references are often coded. This is especially significant if the location reference is used to
define the location for information about various objects between different systems. For intelligent
transport systems (ITS), many different types of real-world objects are addressed. Amongst these,
location referencing of the road network, or components thereof, is a particular focus.
Communication of a location reference for specific geographic phenomena, corresponding to objects
in geographic databases, in a standardized, unambiguous manner is a vital part of an integrated ITS
system in which different applications and sources of geographic data are used. Location referencing
methods (LRM, methods of referencing object instances) differ by applications, by the data model used
to create the database or by the enforced object referencing imposed by the specific mapping system
used to create and store the database. A standardized location referencing method allows for a common
and unambiguous identification of object instances representing the same geographic phenomena in
different geographic databases produced by different vendors, for varied applications and operating on
multiple hardware/software platforms. If ITS applications using digital map databases are to become
widespread, it is necessary for data referencing across various applications to be possible. Information
prepared on one system, such as traffic messages, needs to be interpretable by all receiving systems. A
standardized method to refer to specific object instances is essential in achieving such objectives.
LR activities are currently supported by Japanese, Korean, Australian, Canadian, US and European ITS
bodies. Japan has developed a link specification for vehicle information and communication systems
(VICS). In Europe, the radio data system – traffic message channel (RDS-TMC) traffic messaging system
has been developed. In addition, methods have been developed and refined in the EVIDENCE and
AGORA projects based on intersections identified by geographic coordinates and other intersection
descriptors. In the US, standards for location referencing have been developed to accommodate several
different location referencing methods.
This document provides specifications for location referencing for ITS systems (although other
committees or standardization bodies can subsequently consider extending it to a more generic
context). Other LR methods for transport protocol experts group (TPEG) and geographic information
are defined in the following documents:
— ISO/TS 21219-21, Intelligent transport systems — Traffic and travel information via transport protocol
experts group, generation 2 (TPEG2) — Part 21: Geographic location referencing (TPEG-GLR)
— ISO/TS 21219-22, Intelligent transport systems — Traffic and travel information (TTI) via transport
protocol experts group, generation 2 (TPEG2) — Part 22: OpenLR location referencing (TPEG2-OLR)
— ISO 19148, Geographic information — Linear referencing
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INTERNATIONAL STANDARD ISO 17572-1:2022(E)
Intelligent transport systems (ITS) — Location referencing
for geographic databases —
Part 1:
General requirements and conceptual model
1 Scope
The ISO 17572 series specifies location referencing methods (LRMs) that describe locations in the
context of geographic databases and that are intended for use in locating transport-related phenomena
both in an encoder system and from the decoder side. This document defines what is meant by such
objects and describes the reference in detail, including whether or not components of the reference are
mandatory or optional, and their characteristics.
The ISO 17572 series specifies three different LRMs:
— pre-coded LRM (pre-coded profile);
— dynamic LRM (dynamic profile);
— precise relative LRM (precise relative profile).
The ISO 17572 series does not define a physical format for implementing the LRM. However, the
requirements for physical formats are defined.
The ISO 17572 series does not define details of the location referencing system (LRS), i.e. how the LRMs
are to be implemented in software, hardware or processes.
This document specifies the following general LRM-related subjects:
— requirements of an LRM;
— conceptual data model for LRMs;
— inventory LRMs (see Annex A).
This document also provides:
— examples of conceptual model use (see Annex B);
— a comparison of definitions with ISO/TC 211 (see Annex C).
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
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ISO 17572-1:2022(E)
3.1
accuracy
measure of closeness of results of observations, computations, or estimates to the true values or the
values accepted as being true
3.2
area
two-dimensional, geographical region on the surface of the Earth
Note 1 to entry: An area can be represented as an implicit area or an explicit area.
3.3
area location
two-dimensional location, representing a geographical region on the surface of the Earth
3.4
attribute
characteristic property of a real-world feature
Note 1 to entry: This property allows the identification of a specific feature by its attributes. An attribute has a
defined type and contains a value. Attributes can be either simple, consisting of one atomic value, or composite
(see composite attribute).
3.5
coordinate
one of an ordered set of N numbers designating the position of a point in N-dimensional space
Note 1 to entry: N would be 1, 2 or 3.
3.6
complex intersection
intersection that consists at least of two or more junctions and one or more road elements
3.7
datum
parameter or set of parameters that realize the position of the origin, the scale, and the orientation of a
coordinate system
[SOURCE: ISO 19111:2019, 3.1.15, modified — admitted term ("reference frame") removed.]
3.8
descriptor
characteristic of a geographic object, usually stored as an attribute
EXAMPLE Road names or road numbers.
3.9
digital map database
structured set of digital and alphanumeric data portraying geographic locations and relationships of
spatial features
Note 1 to entry: Typically, such structures represent, but are not limited to, the digital form of hard copy maps.
For example, drawings can be imported into a geographic information system (GIS) and considered as a form of
digital map.
3.10
dynamic location reference
location reference generated on-the-fly based on geographic properties in a digital map database
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3.11
explicit area
two-dimensional face on the surface of the earth, with a specified outline either being a simple
geometric figure or an irregular outline/polygon
3.12
geodetic reference frame
reference frame or datum describing the relationship of a two- or three-dimensional coordinate system
to the Earth
[SOURCE: ISO 19111:2019, 3.1.34, modified — Note 1 to entry has been removed.]
3.13
implicit area
selection of road segments to be referenced belonging to a certain area (subnetwork)
Note 1 to entry: One implicit area can be built up of multiple subnetworks that are geographically connected.
3.14
international terrestrial reference frame
ITRF
Earth-centred global reference frame, including an Earth model, based on satellite and terrestrial data;
realization of the international terrestrial reference system (ITRS)
Note 1 to entry: The ITRF is a realization of the international terrestrial reference system (ITRS). It contains
primary parameters defining the shape, angular velocity and the earth mass of an Earth ellipsoid, and secondary
parameters defining a gravity model of the Earth. Primary parameters are used to derive latitude-longitude
coordinates (horizontal datum). The ITRF94 reference frame is defined in ISO 19161-1.
3.15
international terrestrial reference system
ITRS
reference system for the Earth derived from precise and accurate space geodesy measurements,
not restricted to GNSS Doppler measurements, which is periodically tracked and revised by the
International Earth Rotation and Reference Service
Note 1 to entry: The basic information and the requirements related to the ITRS are defined in ISO 19161-1.
3.16
intersection
crossing and/or connection of two or more roads
Note 1 to entry: In the ISO 20524 series (Geographic Data Files, GDF), an intersection is a level 2 representation of
a junction which bounds a road or a ferry. It is a complex feature, composed of one or more level 1 junctions, road
elements and enclosed traffic areas. The definition in this document is different from that of the ISO 20524 series
because the location referencing system refers to real-world objects rather than a database definition, as defined
in the ISO 20524 series.
Note 2 to entry: Crossings can be at-grade or grade-separated. Crossings that are grade-separated where no
connection between the road segments exists are excluded from this definition.
3.17
road junction
junction
elementary element in the road network, connecting two or more road elements
Note 1 to entry: In the ISO 20524 series (Geographic Data Files, GDF), a junction is a level 1 feature that bounds
a road element or ferry connection. Junctions that represent real crossings are at least trivalent (having three
roads connected). A bivalent junction can only be defined if an attribute change occurs along the road (e.g. road
name change). A junction is also coded at the end of a dead-end road, to terminate it.
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3.18
linear location
location that has a one-dimensional character
EXAMPLE A road segment.
3.19
link
edge
direct topological connection between two nodes that has a unique link ID in a given digital map
database
Note 1 to entry: A link can contain additional intermediate coordinates (shape points) to better represent the
shape of curved features. A link can be directed or undirected.
3.20
link identifier
link ID
identifier that is uniquely assigned to a link
Note 1 to entry: A link identifier can be arbitrary or can be assigned by convention to ensure that no multiple
occurrences of the same identifier will be used within one instance of a network or map database.
3.21
link location
location identifiable by a part of the road network database having one identifier or having a uniquely
identifiable combination of attributes throughout the continuous stretch
Note 1 to entry: One link location can consist of multiple links.
3.22
location
particular place or position
Note 1 to entry: A location is matched to database objects by location definitions, which specify what is meant
by a particular location. Without any explicit remark, it is intended to be a linear stretch in terms of topology in
the database network without any loops or discontinuities in between (linear location). It can also be only a point
in the network as a specialization of a linear stretch with length zero. In addition to that, a location can also be
a set of road elements representing an area. This area is expressible by a polygon or a list of linear locations. For
further description of different categories of locations, refer to 6.4.
[SOURCE: ISO 19112:2019, 3.1.3, modified — The original Note to entry and Example have been
removed. A new Note 1 to entry has been added.]
3.23
location reference
LR
label assigned to a location
Note 1 to entry: With a single location referencing method (LRM), one reference defines unambiguously and
exactly one location in the location referencing system as defined in 5.2. The location reference is the string of
data which is passed between different implementations of a location referencing system to identify the location.
3.24
location definition
actual delineation of exactly what is meant, and therefore what is not meant, by a particular location
within a specific database
Note 1 to entry: It is the precise location definition of the database object, or set of database objects, which is
referenced.
EXAMPLE GDF road elements that make up a particular instance of an ALERT-C location.
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3.25
location referencing
action to assign a label to a location
3.26
location referencing method
LRM
methodology of assigning location references to locations
3.27
location referencing system
LRS
complete system by which location references are generated, according to a location referencing
method, and communicated, including standards, definitions, software, hardware, and databases
3.28
matching
translation of a location reference to a specific object in a given map database to attempt
recognition of the same identified object in both the sender's and the receiver's map database
Note 1 to entry: Matching is seen as a subsequent part to the method of decoding a location reference adhering to
the defined LRM.
3.29
node
zero-dimensional element that is a topological junction of two or more edges or an end point of an edge
Note 1 to entry: A node is created for topologically significant points, such as simple intersections of roads or
other linear features including boundaries, but also for locations such as electric beacons, kilometre-posts, or
sensors detecting traffic flows, these being significant points specified in a map.
3.30
point
zero-dimensional element that specifies geometric location
Note 1 to entry: One coordinate pair or triplet specifies the location.
3.31
point location
location with a zero-dimensional character
EXAMPLE A simple crossing.
3.32
precision
closeness of agreement between indications or measured quantity values obtained by replicate
measurements on the same or similar objects
Note 1 to entry: Alternatively, the closeness of measurements of the same phenomenon repeated under exactly
the same conditions and using the same techniques.
[SOURCE: ISO/IEC Guide 99:2007, 2.15, modified — The Note to entry and Example have been removed.
A new Note 1 to entry has been added.]
3.33
pre-coded location reference
location reference using a unique identifier that is agreed upon in both a sender and receiver system to
select a location from a set of pre-coded locations
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3.34
quad tree
hierarchical data structure which, on a next lower level, subdivides a given area into four quadrants of
the same size where any level has knowledge of its four sublevels and its parent level
3.35
relationship
semantic or topological interrelation or dependency between locations in the location referencing
system (LRS)
Note 1 to entry: Relationships can exist between locations in the LRS. These relationships will generally
be structured to allow more sophisticated use of the location reference, such as a topological or hierarchical
structure. For example, a county location can be defined as an aggregate of several city locations or a long
stretch of road can be an aggregate of several smaller road segments. Referencing the county can be easier than
referencing all the cities which make up the county. This allows scalability and ease of use in the LRSs using the
location referencing method (LRM).
Note 2 to entry: The term definition in ISO/TC 211 is different because of the difference in conceptual level
between the groups.
3.36
road
part of the road network which is generally considered as a whole and which can be addressed by a
single identification like a road name or road number throughout
Note 1 to entry: In general, it is a connection within the road network, with or without crossings, which
functionally can be considered as a unity. A road with multiple (associated) carriageways can be considered as
one road. Within the ISO 17572 series, the term also covers the natural language term "street".
Note 2 to entry: The subsequent parts of this document intentionally do not make direct use of this term because
under different circumstances it is not always possible to define exactly where a road ends. For this reason,
reference is made to artificial but more precisely-definable road elements or road sections of the road network.
3.37
road crossing
location where two or more roads connect or intersect
Note 1 to entry: A road crossing can be “simple”, corresponding to one junction, or “complex”, including internal
road elements and junctions.
3.38
road element
linear section of the road network which is designed for vehicular movement having a junction at each
end
Note 1 to entry: It serves as the smallest unit of the road network at GDF level 1 that is independent.
3.39
road section
road segment that is bounded by two intersections and has the same attributes throughout
Note 1 to entry: Generally, the two intersections are different, only in some specific cases are the intersections
the same, e.g. a tear-drop street or slip roads inside of complex intersections.
3.40
road segment
part of a road, having its start and end along that road
Note 1 to entry: An important difference between a road section and road segment is that the segment does not
necessarily end at intersections.
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3.41
shape point
intermediate coordinate pair to represent the shape of curved features
3.42
subnetwork
plurality of road segments lying in geographical or topological conjunction to each other
3.43
topology
properties of spatial configuration invariant under continuous transformation
Note 1 to entry: In a digital map database, this means the logical relationships among map features. It can be
used to characterize spatial relationships such as connectivity and adjacency.
4 Abbreviated terms
AGORA implementation of global location referencing approach
(name of a European Union project 2000–2002)
ALERT-C advice and problem location for European road traffic-compact
EVIDENCE extensive validation of identification concepts in Europe
(name of a European Union project 1998–1999)
GDF geographic data file
GIS geographic information system
GNSS global navigation satellite system
ITS intelligent transport systems
POI point of interest
RDS radio data system
TPEG transport protocol expert group
TMC traffic message channel
TTI traffic and traveller information
UML unified modelling language
UTM universal transverse mercator
VICS vehicle information and communication system
NOTE The ISO 17572 series uses unified modelling language (UML) to express specific circumstances. As
such, graphical elements are used to express specific constraints and structural relationships. A full definition
can be found in the ISO/IEC 19505 series.
5 Objectives and requirements for a location referencing method
5.1 Objectives for an optimal location referencing method
ITS applications have different objectives regarding location referencing, which from their
contradictory nature, cannot be fulfilled completely. In theory, an ideal location referencing method
would require every LRS to have at a given time the same, completely accurate map and all locations
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would be identifiable without any additional computational effort. Even though this is not achievable,
the following goals should guide the definition and optimization of a location referencing method. The
circumstances of the specific location referencing system can give different weight to the following
goals.
1) The LRM should be simple enough to be implemented in a resource- and
performance-efficient way.
This first goal states that processing power in any case is a cost factor to be minimized.
2) The LRM should not unduly add to the volume of data to be transferred.
Location referencing implies at least two systems communicating with each other. Communication
also causes costs and therefore needs to be minimized.
3) The LRM should provide location references with the highest accuracy possible.
This means that the aim should be to use the exact location, both in the sender and the receiver
system. In many cases, it will be up to the receiver to decode the location reference as well as
possible. To help the receiver to do so, it shall be implied that the sending system sends the location
reference as accurately as possible.
5.2 Requirements of the location referencing method
In addition to the goals, a number of minimal requirements shall make the different location referencing
methods feasible for the foreseen categories of locations (see 6.4).
One of the most important data characteristics for ITS applications is spatial accuracy. Spatial accuracy
is an aspect of data quality and is described in ISO 20524-1 in the following way: "The shape of a level
0 edge including all positions on the segment as a whole shall not have any position that diverges from the
real shape more than an allowed error." Spatial data accuracy requirements for ITS vary accordi
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