EN ISO 19111:2007

SLOVENSKI STANDARD
01-junij-2008
1DGRPHãþD
SIST EN ISO 19111:2005
Geografske informacije - Lociranje s koordinatami (ISO 19111:2007)
Geographic information - Spatial referencing by coordinates (ISO 19111:2007)
Geoinformation - Koordinatenreferenzsysteme (ISO 19111:2007)
Information géographique - Systeme de références spatiales par coordonnées (ISO
19111:2007)
Ta slovenski standard je istoveten z: EN ISO 19111:2007
ICS:
07.040 Astronomija. Geodezija. Astronomy. Geodesy.
Geografija Geography
35.240.70 Uporabniške rešitve IT v IT applications in science
znanosti
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 19111
NORME EUROPÉENNE
EUROPÄISCHE NORM
July 2007
ICS 35.240.70 Supersedes EN ISO 19111:2005
English Version
Geographic information - Spatial referencing by coordinates
(ISO 19111:2007)
Information géographique - Système de références Geoinformation - Raumbezug durch Koordinaten (ISO
spatiales par coordonnées (ISO 19111:2007) 19111:2007)
This European Standard was approved by CEN on 30 June 2007.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
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© 2007 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 19111:2007: E
worldwide for CEN national Members.

Foreword
This document (EN ISO 19111:2007) has been prepared by Technical Committee ISO/TC 211
"Geographic information/Geomatics" in collaboration with Technical Committee CEN/TC 287
"Geographic Information", the secretariat of which is held by NEN.

This European Standard shall be given the status of a national standard, either by publication of
an identical text or by endorsement, at the latest by January 2008, and conflicting national
standards shall be withdrawn at the latest by January 2008.

This document supersedes EN ISO 19111:2005.

According to the CEN/CENELEC Internal Regulations, the national standards organizations of
the following countries are bound to implement this European Standard: Austria, Belgium,
Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United
Kingdom.
Endorsement notice
The text of ISO 19111:2007 has been approved by CEN as EN ISO 19111:2007 without any
modifications.
INTERNATIONAL ISO
STANDARD 19111
Second edition
2007-07-01
Geographic information — Spatial
referencing by coordinates
Information géographique — Système de références spatiales par
coordonnées
Reference number
ISO 19111:2007(E)
©
ISO 2007
ISO 19111:2007(E)
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ii © ISO 2007 – All rights reserved

ISO 19111:2007(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Conformance requirements. 1
3 Normative references . 1
4 Terms and definitions. 2
5 Conventions . 7
5.1 Symbols . 7
5.2 Abbreviated terms . 7
5.3 UML notation. 8
5.4 Attribute status . 9
6 Spatial referencing by coordinates — Overview . 9
6.1 Relationship between coordinates and coordinate reference system. 9
6.2 UML model for spatial referencing by coordinates — Overview . 11
7 Identified Object package . 12
7.1 General. 12
7.2 UML schema for the Identified Object package. 12
8 Coordinate Reference System package . 15
8.1 Reference system . 15
8.2 Coordinate reference system . 15
8.3 UML schema for the Coordinate Reference System package . 17
9 Coordinate System package. 23
9.1 Introduction . 23
9.2 Coordinate system. 23
9.3 Coordinate system axis . 24
9.4 UML schema for the Coordinate System package . 25
10 Datum package . 34
10.1 Types of datums . 34
10.2 Geodetic datum. 34
10.3 UML schema for the Datum package.34
11 Coordinate Operation package . 41
11.1 General characteristics of coordinate operations. 41
11.2 UML schema for the Coordinate Operation package. 41
Annex A (normative) Abstract test suite. 51
Annex B (informative) Context for modelling of spatial referencing by coordinates . 53
Annex C (informative) Spatial referencing by coordinates – Geodetic concepts. 62
Annex D (informative) Examples . 65
Annex E (informative) Recommended best practice for interfacing to ISO 19111 . 77
Bibliography . 78

ISO 19111:2007(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.
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 19111 was prepared by Technical Committee ISO/TC 211, Geographic information/Geomatics, in close
collaboration with the Open Geospatial Consortium (OGC).
This second edition cancels and replaces the first edition (ISO 19111:2003), which has been technically
revised.
iv © ISO 2007 – All rights reserved

ISO 19111:2007(E)
Introduction
Geographic information contains spatial references which relate the features represented in the data to
positions in the real world. Spatial references fall into two categories:
⎯ those using coordinates;
⎯ those based on geographic identifiers.
[4]
Spatial referencing by geographic identifiers is defined in ISO 19112 . This International Standard describes
the data elements, relationships and associated metadata required for spatial referencing by coordinates. It
describes the elements that are necessary to fully define various types of coordinate systems and coordinate
reference systems applicable to geographic information. The subset of elements required is partially
dependent upon the type of coordinates. This International Standard also includes optional fields to allow for
the inclusion of non-essential coordinate reference system information. The elements are intended to be both
machine and human readable.
The traditional separation of horizontal and vertical position has resulted in coordinate reference systems that
are horizontal (2D) and vertical (1D) in nature, as opposed to truly three-dimensional. It is established practice
to define a three-dimensional position by combining the horizontal coordinates of a point with a height or depth
from a different coordinate reference system. In this International Standard, this concept is defined as a
compound coordinate reference system.
The concept of coordinates can be expanded from a strictly spatial context to include time. ISO 19108
describes temporal schema. Time can be added as a temporal coordinate reference system within a
compound coordinate reference system. It is even possible to add two time-coordinates, provided the two
coordinates describe different independent quantities.
EXAMPLE An example is the time/space position of a subsurface point of which the vertical coordinate is expressed
as the two-way travel time of a sound signal in milliseconds, as is common in seismic imaging. A second time-coordinate
indicates the time of observation, usually expressed in whole years.
Certain scientific communities use three-dimensional systems where horizontal position is combined with a
non-spatial parameter. In these communities, the parameter is considered to be a third, vertical axis. The
parameter, although varying monotonically with elevation or depth, does not necessarily vary in a simple
manner; thus, conversion from the parameter to height or depth is non-trivial. The parameters concerned are
normally absolute measurements and the datum is taken with reference to a direct physical measurement of
the parameter. These non-spatial parameters are beyond the scope of this International Standard. However,
the modelling constructs described within this International Standard can be applied through a profile specific
to a community.
In addition to describing a coordinate reference system, this International Standard provides for the
description of a coordinate transformation or a coordinate conversion between two different coordinate
reference systems. With such information, spatial data referred to different coordinate reference systems can
be related to one specified coordinate reference system. This facilitates spatial data integration. Alternatively,
an audit trail of coordinate reference system manipulations can be maintained.

INTERNATIONAL STANDARD ISO 19111:2007(E)

Geographic information — Spatial referencing by coordinates
1 Scope
This International Standard defines the conceptual schema for the description of spatial referencing by
coordinates, optionally extended to spatio-temporal referencing. It describes the minimum data required to
define one-, two- and three-dimensional spatial coordinate reference systems with an extension to merged
spatial-temporal reference systems. It allows additional descriptive information to be provided. It also
describes the information required to change coordinates from one coordinate reference system to another.
In this International Standard, a coordinate reference system does not change with time. For coordinate
reference systems defined on moving platforms such as cars, ships, aircraft and spacecraft, the
transformation to an Earth-fixed coordinate reference system can include a time element.
This International Standard is applicable to producers and users of geographic information. Although it is
applicable to digital geographic data, its principles can be extended to many other forms of geographic data
such as maps, charts and text documents.
The schema described can be applied to the combination of horizontal position with a third non-spatial
parameter which varies monotonically with height or depth. This extension to non-spatial data is beyond the
scope of this International Standard but can be implemented through profiles.
2 Conformance requirements
This International Standard defines two classes of conformance, Class A for conformance of coordinate
reference systems and Class B for coordinate operations between two coordinate reference systems. Any
coordinate reference system claiming conformance to this International Standard shall satisfy the
requirements given in A.1. Any coordinate operation claiming conformance to this International Standard shall
satisfy the requirements given in A.2.
3 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the cited edition applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO/TS 19103, Geographic information — Conceptual schema language
ISO 19108, Geographic information — Temporal schema
ISO 19115, Geographic information — Metadata
Normative reference to ISO 19115 is restricted as follows. In this International Standard, normative reference
to ISO 19115 excludes the MD_CRS class and its component classes. ISO 19115 class MD_CRS and its
component classes specify descriptions of coordinate reference systems elements. These elements are
modelled in this International Standard.
NOTE The MD_CRS class and its component classes were deleted from ISO 19115:2003 through Technical
Corrigendum 1:2006.
ISO 19111:2007(E)
4 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
4.1
affine coordinate system
coordinate system in Euclidean space with straight axes that are not necessarily mutually perpendicular
4.2
Cartesian coordinate system
coordinate system which gives the position of points relative to n mutually perpendicular axes
NOTE n is 2 or 3 for the purposes of this International Standard.
4.3
compound coordinate reference system
coordinate reference system using at least two independent coordinate reference systems
NOTE Coordinate reference systems are independent of each other if coordinate values in one cannot be converted
or transformed into coordinate values in the other.
4.4
concatenated operation
coordinate operation consisting of sequential application of multiple coordinate operations
4.5
coordinate
one of a sequence of n numbers designating the position of a point in n-dimensional space
NOTE In a coordinate reference system, the coordinate numbers are qualified by units.
4.6
coordinate conversion
coordinate operation in which both coordinate reference systems are based on the same datum
EXAMPLE Conversion from an ellipsoidal coordinate reference system based on the WGS 84 datum to a Cartesian
coordinate reference system also based on the WGS 84 datum, or change of units such as from radians to degrees or feet
to meters.
NOTE A coordinate conversion uses parameters which have specified values that are not determined empirically.
4.7
coordinate operation
change of coordinates, based on a one-to-one relationship, from one coordinate reference system to
another
NOTE Supertype of coordinate transformation and coordinate conversion.
4.8
coordinate reference system
coordinate system that is related to an object by a datum
NOTE For geodetic and vertical datums, the object will be the Earth.
4.9
coordinate set
collection of coordinate tuples related to the same coordinate reference system
2 © ISO 2007 – All rights reserved

ISO 19111:2007(E)
4.10
coordinate system
set of mathematical rules for specifying how coordinates are to be assigned to points
4.11
coordinate transformation
coordinate operation in which the two coordinate reference systems are based on different datums
NOTE A coordinate transformation uses parameters which are derived empirically by a set of points with known
coordinates in both coordinate reference systems.
4.12
coordinate tuple
tuple composed of a sequence of coordinates
NOTE The number of coordinates in the coordinate tuple equals the dimension of the coordinate system; the order of
coordinates in the coordinate tuple is identical to the order of the axes of the coordinate system.
4.13
cylindrical coordinate system
three-dimensional coordinate system with two distance and one angular coordinates
4.14
datum
parameter or set of parameters that define the position of the origin, the scale, and the orientation of a
coordinate system
4.15
depth
distance of a point from a chosen reference surface measured downward along a line perpendicular to that
surface
NOTE A depth above the reference surface will have a negative value.
4.16
easting
E
distance in a coordinate system, eastwards (positive) or westwards (negative) from a north-south reference
line
4.17
ellipsoid
surface formed by the rotation of an ellipse about a main axis
NOTE In this International Standard, ellipsoids are always oblate, meaning that the axis of rotation is always the
minor axis.
4.18
ellipsoidal coordinate system
geodetic coordinate system
coordinate system in which position is specified by geodetic latitude, geodetic longitude and (in the three-
dimensional case) ellipsoidal height
4.19
ellipsoidal height
geodetic height
h
distance of a point from the ellipsoid measured along the perpendicular from the ellipsoid to this point,
positive if upwards or outside of the ellipsoid
NOTE Only used as part of a three-dimensional ellipsoidal coordinate system and never on its own.
ISO 19111:2007(E)
4.20
engineering coordinate reference system
coordinate reference system based on an engineering datum
EXAMPLES Local engineering and architectural grids; coordinate reference system local to a ship or an orbiting
spacecraft.
4.21
engineering datum
local datum
datum describing the relationship of a coordinate system to a local reference
NOTE Engineering datum excludes both geodetic and vertical datums.
EXAMPLE A system for identifying relative positions within a few kilometres of the reference point.
4.22
flattening
f
ratio of the difference between the semi-major (a) and semi-minor axis (b) of an ellipsoid to the semi-major
axis; f = (a – b)/a
NOTE Sometimes inverse flattening 1/f = a/(a − b) is given instead; 1/f is also known as reciprocal flattening.
4.23
geodetic coordinate reference system
coordinate reference system based on a geodetic datum
4.24
geodetic datum
datum describing the relationship of a two- or three-dimensional coordinate system to the Earth
4.25
geodetic latitude
ellipsoidal latitude
ϕ
angle from the equatorial plane to the perpendicular to the ellipsoid through a given point, northwards treated
as positive
4.26
geodetic longitude
ellipsoidal longitude
λ
angle from the prime meridian plane to the meridian plane of a given point, eastward treated as positive
4.27
geoid
equipotential surface of the Earth’s gravity field which is everywhere perpendicular to the direction of gravity
and which best fits mean sea level either locally or globally
4.28
gravity-related height
H
height dependent on the Earth’s gravity field
NOTE This refers to in particular orthometric height or normal height, which are both approximations of the distance
of a point above the mean sea level.
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ISO 19111:2007(E)
4.29
height
h, H
distance of a point from a chosen reference surface measured upward along a line perpendicular to that
surface
NOTE A height below the reference surface will have a negative value.
4.30
image coordinate reference system
coordinate reference system based on an image datum
4.31
image datum
engineering datum which defines the relationship of a coordinate system to an image
4.32
linear coordinate system
one-dimensional coordinate system in which a linear feature forms the axis
EXAMPLES Distances along a pipeline; depths down a deviated oil well bore.
4.33
map projection
coordinate conversion from an ellipsoidal coordinate system to a plane
4.34
mean sea level
average level of the surface of the sea over all stages of tide and seasonal variations
NOTE Mean sea level in a local context normally means mean sea level for the region calculated from observations
at one or more points over a given period of time. Mean sea level in a global context differs from a global geoid by not
more than 2 m.
4.35
meridian
intersection of an ellipsoid by a plane containing the shortest axis of the ellipsoid
NOTE This term is often used for the pole-to-pole arc rather than the complete closed figure.
4.36
northing
N
distance in a coordinate system, northwards (positive) or southwards (negative) from an east-west reference
line
4.37
polar coordinate system
two-dimensional coordinate system in which position is specified by distance and direction from the origin
NOTE For the three-dimensional case, see spherical coordinate system (4.44).
4.38
prime meridian
zero meridian
meridian from which the longitudes of other meridians are quantified
ISO 19111:2007(E)
4.39
projected coordinate reference system
coordinate reference system derived from a two-dimensional geodetic coordinate reference system by
applying a map projection
4.40
semi-major axis
a
semi-diameter of the longest axis of an ellipsoid
NOTE This equates to the semi-diameter of the ellipsoid measured in its equatorial plane.
4.41
semi-minor axis
b
semi-diameter of the shortest axis of an ellipsoid
NOTE The shortest axis coincides with the rotation axis of the ellipsoid and therefore contains both poles.
4.42
sequence
finite, ordered collection of related items (objects or values) that may be repeated
[ISO 19107]
4.43
spatial reference
description of position in the real world
NOTE This may take the form of a label, code or coordinate tuple.
4.44
spherical coordinate system
three-dimensional coordinate system with one distance measured from the origin and two angular
coordinates, commonly associated with a geodetic coordinate reference system
NOTE Not to be confused with an ellipsoidal coordinate system based on an ellipsoid ‘degenerated’ into a sphere.
4.45
tuple
ordered list of values
[ISO 19136]
4.46
unit
defined quantity in which dimensioned parameters are expressed
NOTE In this International Standard, the subtypes of units are length units, angular units, time units, scale units and
pixel spacing units.
4.47
vertical coordinate reference system
one-dimensional coordinate reference system based on a vertical datum
4.48
vertical coordinate system
one-dimensional coordinate system used for gravity-related height or depth measurements
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ISO 19111:2007(E)
4.49
vertical datum
datum describing the relation of gravity-related heights or depths to the Earth
NOTE In most cases, the vertical datum will be related to mean sea level. Ellipsoidal heights are treated as related to
a three-dimensional ellipsoidal coordinate system referenced to a geodetic datum. Vertical datums include sounding
datums (used for hydrographic purposes), in which case the heights may be negative heights or depths.
5 Conventions
5.1 Symbols
a semi-major axis
b semi-minor axis
E easting
f flattening
H gravity-related height
h ellipsoidal height
N northing
λ geodetic longitude
ϕ geodetic latitude
E, N Cartesian coordinates in a projected coordinate reference system
X, Y, Z Cartesian coordinates in a geodetic coordinate reference system
i, j, [k] Cartesian coordinates in an engineering coordinate reference system
r, θ polar coordinates in a 2D engineering coordinate reference system
r, Ω, θ spherical coordinates in a 3D engineering or geodetic coordinate reference system
5.2 Abbreviated terms
CC change coordinates (package abbreviation in UML model)
CD coordinate datum (package abbreviation in UML model)
CCRS compound coordinate reference system
CRS coordinate reference system
CS coordinate system (also, package abbreviation in UML model)
IO identified object (package abbreviation in UML model)
MSL mean sea level
ISO 19111:2007(E)
pixel a contraction of “picture element”, the smallest element of a digital image to which attributes are
assigned
RS reference system (package abbreviation in UML model)
SC spatial referencing by coordinates (package abbreviation in UML model)
SI le Système International d’unités
UML Unified Modeling Language
URI Uniform Resource Identifier
1D one-dimensional
2D two-dimensional
3D three-dimensional
5.3 UML notation
In this International Standard, the conceptual schema for describing coordinate reference systems and
coordinate operations is modelled with the Unified Modelling Language (UML). The basic data types and UML
[9]
diagram notations are defined in ISO/TS 19103 and ISO/IEC 19501 .
In this International Standard, the following stereotypes of UML classes are used:
a) <> a descriptor of a set of values that lack identity (independent existence and the
possibility of side effects); a DataType is a class with no operations whose primary
purpose is to hold the information;
b) <>  a class used for specification of a domain of objects together with operations applicable
to the objects;
c) <> a flexible enumeration that uses string values for expressing a list of potential values;
d) <>  contains a list of attributes where only one of those attributes can be present at any
time.
The following data types defined in ISO/TS 19103 are used:
⎯ Angle   amount of rotation required to bring one line or plane into coincidence with another;
⎯ Boolean  a value specifying TRUE or FALSE;
⎯ CharacterString  a sequence of characters;
⎯ Date   a character string which comprises year, month and day in the format as specified by
ISO 8601;
⎯ GenericName a generic name structure in the context of namespaces, defined in ISO/TS 19103;
⎯ Integer  an integer number;
⎯ Length   the measure of distance;
⎯ Measure  result from performing the act or process of ascertaining the extent, dimensions or
quantity of some entity;
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ISO 19111:2007(E)
⎯ Number  abstract class that can be subtyped to a specific number type (real, integer, decimal,
double, float);
⎯ Scale   the ratio of one quantity to another;
⎯ Unit of Measure  any of the systems devised to measure some physical quantity.
In addition, a Sequence type of collection is used, which contains an ordered list of values with the specified
data type. The format used is “Sequence”.
In the UML diagrams in this International Standard, grey boxes indicate classes from other packages.
5.4 Attribute status
In this International Standard, attributes are given an obligation status:
Obligation Definition Meaning
M mandatory This attribute shall be supplied.
C conditional This attribute shall be supplied if the condition (given in the attribute
description) is true. It may be supplied if the condition is false.
O optional This attribute may be supplied.
In this International Standard, the Maximum Occurrence column indicates the maximum number of
occurrences of attribute values that are permissible, with N indicating no upper limit.
6 Spatial referencing by coordinates — Overview
6.1 Relationship between coordinates and coordinate reference system
In this International Standard, a coordinate is one of n scalar values that define the position of a single point.
In other contexts, the term ordinate is used for a single value and coordinate for multiple ordinates. Such
usage is not part of this International Standard.
A coordinate tuple is an ordered list of n coordinates that define the position of a single point. In this
International Standard, the coordinate tuple shall be composed of one, two or three spatial coordinates. The
coordinates shall be mutually independent and their number shall be equal to the dimension of the coordinate
space.
EXAMPLE A coordinate tuple cannot contain two heights.
Coordinates are ambiguous until the system to which those coordinates are related has been fully defined.
Without the full specification of the system, coordinates are ambiguous at best and meaningless at worst.
A coordinate reference system (CRS) defines the coordinate space such that the coordinate values are
unambiguous. In this International Standard, the order of the coordinates within the coordinate tuple and their
unit(s) of measure shall be parts of the coordinate reference system definition.
In this International Standard, a coordinate set shall be a collection of coordinate tuples referenced to the
same coordinate reference system. A CRS identification or definition in accordance with this International
Standard shall be associated with every coordinate tuple. If only one point is being described, the association
shall be direct. For a coordinate set, one CRS identification or definition may be associated with the
coordinate set and then all coordinate tuples in that coordinate set inherit that association. The conceptual
relationship of coordinate tuple and coordinate set to coordinate reference system is shown in Figure 1.
ISO 19111:2007(E)
Figure 1 — Conceptual relationship of coordinates to coordinate reference system
The semantic meaning of coordinate tuple and coordinate set is reflected in the modelling of classes
[3]
DirectPosition and GM_Object respectively; this modelling is in ISO 19107 .
In this International Standard, a coordinate reference system shall be comprised of one coordinate system
and one datum (see Figure 2).
Figure 2 — Conceptual model of a coordinate reference system
The high level abstract model for spatial referencing by coordinates is shown in Figure 3. A coordinate
transformation or coordinate conversion operates on coordinates, not on coordinate reference systems.
[3]
Coordinate operation has been modelled in ISO 19107 by the operation “Transform” of the GM_Object
class.
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ISO 19111:2007(E)
NOTE A coordinate operation may be single or concatenated. Refer to Clause 11.
Figure 3 — Conceptual model for spatial referencing by coordinates
The description of quality of a spatial reference is covered by the provisions of ISO 19115.
6.2 UML model for spatial referencing by coordinates — Overview
The specification for spatial referencing by coordinates is defined in this International Standard in the form of a
UML model with supplementary text. The UML model contains five primary UML packages, as shown in
Figure 4. Each box represents a package, and contains the package name. Each arrowed line shows the
dependency (at the head of the arrow) of one package upon another package.

Figure 4 — UML model packages and dependencies
The five UML packages for spatial referencing by coordinates are more completely specified in the Clauses 7
through 11. Further context for the requirements of Clauses 7 through 11 is given in Annex B and some
geodetic concepts underpinning spatial referencing by coordinates are given in Annex C. Examples illustrating
how this International Standard can be applied when defining a coordinate reference system or a coordinate
operation are given in Annex D. Recommendations for referencing to classes defined in this International
Standard are given in Annex E.
ISO 19111:2007(E)
7 Identified Object package
7.1 General
The Identified Object package contains attributes common to several objects used in spatial referencing by
coordinates. These objects – including datum, ellipsoid, coordinate system axis and coordinate operation –
inherit attribute values from the Identified Object package.
One of the attributes is the object primary name. This may have alternative names or aliases.
EXAMPLE 1 A datum name might be “North American Datum of 1983” and its abbreviation “NAD83”.
Object primary names have a data type RS_Identifier which is defined in ISO 19115 whilst aliases have a data
type GenericName which is defined in ISO/TS 19103.
Another attribute is identifier. This is a unique code used to reference an object in a given place.
EXAMPLE 2 A register of geodetic codes and parameters might give the NAD83 datum a unique code of “6269”.
Identifiers have a data type of RS_Identifier.
In addition to the use of an identifier as a reference to a definition in a register of geodetic codes and
parameters, it may also be included in an object definition to allow reference to the object.
Object identification shall be through
a) a full object description as defined in this International Standard, or
b) reference to a full object description in a register of geodetic parameters (the reference is made to the
register's object identifier), or
c) both full description and reference to a description in a register. If there is a conflict between the two, the
register description shall prevail.
a) and b) are alternative means of providing a full object description. b) is recommended for simplicity, but if
the object description is not available from a register, it shall be given explicitly and in full. In both methods,
the order of coordinates in each coordinate tuple shall be as given in the coordinate system description.
When using method b), reference to a geodetic register, applications that are required only to confirm the
identification of an object can do so through the register citation and the object unique identifier from that
register. They do not need to retrieve the elements that constitute the full object description from the register
unless there is a need to quote these or to perform a coordinate operation on the coordinate set.
NOTE Implementers are warned that in any register, errors in the data may be corrected in accordance with rules
specific to that register and defined by the responsible registration authority. The rules for dealing with erroneous data
need to be recognized by applications referencing the register in order to be able to find the data that is required, i.e.
usually the most up-to-date register information, but sometimes, because historically it was used to transform spatial data
that is still in use, the erroneous information from the past.
7.2 UML schema for the Identified Object package
Figure 5 shows the UML class diagram of the IO_IdentifiedObject package. The definition of the object
classes are provided in Tables 1 and 2.
NOTE Through its subclassing from RS_ReferenceSystem which is defined in ISO 19115, SC_CRS inherits the
attribute name. Because of this inheritance, the SC_CRS class does not use IO_IdentifiedObject for its primary name. But
like other classes described in this International Standard, it may use the alias attribute from IO_IdentifiedObjectBase for
aliases.
12 © ISO 2007 – All rights reserved

ISO 19111:2007(E)
Figure 5 — IO_IdentifiedObject package
ISO 19111:2007(E)
Table 1 — Defining elements of IO_IdentifiedObjectBase class
Description: Supplementary identification and remarks information for a CRS or CRS-related object.
Stereotype: Type
Class attribute: Abstract
Inheritance from: (none)
Association roles: (none)
Used by: SC_CRS
CS_CoordinateSystem
CS_CoordinateSystemAxis
CD_Datum
CD_Ellipsoid
CD_PrimeMeridian
CC_CoordinateOperation
CC_OperationMethod
CC_GeneralOperationParameter
Public attributes:
Attribute name UML identifier Data type Obligation Maximum Attribute description
Occurrence
Object alias alias GenericName O N An alternative name by which this object is
identified.
Object identifier identifier RS_Identifier O N An identifier which references elsewhere the
object's defining information; alternatively an
identifier by which this object can be
referenced.
Object remarks remarks CharacterString O 1 Comments on or information about this
object, including data source information.
Table 2 — Defining elements of IO_IdentifiedObject class
Description: Identifications of a CRS-related object.
Stereotype: Type
Class attribute: Abstract
Inheritance from: IO_IdentifiedObjectBase
Association roles: (none)
Used by: CS_CoordinateSystem
CS_CoordinateSystemAxis
CD_Datum
CD_Ellipsoid
CD_PrimeMeridian
CC_CoordinateOperation
CC_OperationMethod
CC_GeneralOperationParameter
Public attributes: 3 attributes (identifier, alias and remarks) inherited from IO_IdentifiedObjectBase, plus:
Attribute name UML identifier Data type Obligation Maximum Attribute description
Occurrence
Object name name RS_Identifier M 1 The primary name by which this object is
identified.
14 © ISO 2007 – All rights reserved

ISO 19111:2007(E)
8 Coordinate Reference System package
8.1 Reference system
A reference system contains the metadata required to interpret spatial location information unambiguously.
Two methods to describe spatial location are distinguished.
a) Spatial referencing by geographic identifier. Geographic identifiers are location descriptors such as
addresses and grid indexes. Such systems fall outside the scope of this International Standard and the
associated model. The requirements for spatial referencing by geographic identifier are described in
[4]
ISO 19112 .
b) Spatial referencing by coordinates. The scope of this International Standard and the associated UML
model is confined to the description of position through coordinates.
The RS_ReferenceSystem package and datatypes are described in ISO 19115. Table 3 shows the attributes
inherited by the CRS class.
Table 3 — Attributes of RS_ReferenceSystem class inherited from ISO 19115
Attribute name UML identifier Data type Obligation Maximum Attribute description
Occurrence
Reference system name name RS_
...