prEN ISO 6709

Standard representation of geographic point location by coordinates (ISO/DIS 6709:2020)

Standarddarstellung für geographische Punkte durch Koordinaten (ISO/DIS 6709:2020)

Représentation normalisée de la localisation des points géographiques par coordonnées (ISO/DIS 6709:2020)

Standardna predstavitev geografske točkovne lokacije s koordinatami (ISO/DIS 6709:2020)

General Information

• Status: Not Published
• ICS: 35.040 - Information coding
• ICS: 35.240.70 - IT applications in science
• Technical Committee: CEN/TC 287 - Geographic Information
• Drafting Committee: CEN/TC 287 - Geographic Information
• Current Stage: 6055 - CEN Ratification completed (DOR) - Publishing
• Due Date: 05-Jul-2021
• Completion Date: 05-Jul-2021
• Ref Project: oSIST prEN ISO 6709:2021 - Standard representation of geographic point location by coordinates (ISO/DIS 6709:2020)

RELATIONS

• Revised: EN ISO 6709:2009 - Standard representation of geographic point location by coordinates (ISO 6709:2008, including Cor 1:2009)
• Effective Date: 27-Dec-2017

Standards Content (sample)

SLOVENSKI STANDARD
oSIST prEN ISO 6709:2021
01-februar-2021
Standardna predstavitev geografske točkovne lokacije s koordinatami (ISO/DIS
6709:2020)
Standard representation of geographic point location by coordinates (ISO/DIS
6709:2020)

Standarddarstellung für geographische Punkte durch Koordinaten (ISO/DIS 6709:2020)

Représentation normalisée de la localisation des points géographiques par coordonnées

(ISO/DIS 6709:2020)
Ta slovenski standard je istoveten z: prEN ISO 6709
ICS:
07.040 Astronomija. Geodezija. Astronomy. Geodesy.
Geografija Geography
35.240.70 Uporabniške rešitve IT v IT applications in science
znanosti
oSIST prEN ISO 6709:2021 en,fr,de

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

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oSIST prEN ISO 6709:2021
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oSIST prEN ISO 6709:2021
DRAFT INTERNATIONAL STANDARD
ISO/DIS 6709
ISO/TC 211 Secretariat: SIS
Voting begins on: Voting terminates on:
2020-12-28 2021-03-22
Standard representation of geographic point location by
coordinates

Représentation normalisée de la localisation des points géographiques par coordonnées

ICS: 35.240.70
THIS DOCUMENT IS A DRAFT CIRCULATED
This document is circulated as received from the committee secretariat.
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
ISO/CEN PARALLEL PROCESSING
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 6709:2020(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION. ISO 2020
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ISO/DIS 6709:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
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Contents Page

Foreword ........................................................................................................................................................................................................................................iv

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

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

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

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

4 Abbreviated terms, and changes from the previous edition................................................................................... 4

4.1 Abbreviated terms ............................................................................................................................................................................... 4

4.2 Character code notations ............................................................................................................................................................... 5

4.3 Changes from the previous edition and backwards compatibility ............................................................ 5

4.4 Cultural and language adaptability ....................................................................................................................................... 5

5 Conformance ............................................................................................................................................................................................................. 6

6 Geographic point location representation ................................................................................................................................ 6

6.1 Overview ...................................................................................................................................................................................................... 6

6.2 Component representation .......................................................................................................................................................... 7

6.3 Coordinate tuple .................................................................................................................................................................................... 7

6.4 Character string delimiters and terminator notation ........................................................................................... 7

6.5 CRS identifier structure ................................................................................................................................................................... 8

6.6 Text string representation..........................................................................................................................................................10

6.6.1 Background........................................................................................................................................................................10

6.6.2 Formatting rules for angular measures ....................................................................................................10

6.6.3 Component structure ................................................................................................................................................12

7 Human-readable GPL representation .........................................................................................................................................16

Annex A (normative) Conformance and abstract test suite .......................................................................................................20

Annex B (normative) Backwards compatible representation of geographic point location ..................23

Annex C (informative) Latitude and longitude coordinates are not unique.............................................................29

Annex D (informative) Latitude and longitude resolution .........................................................................................................30

Annex E (informative) Changes from ISO 6709:2008 .......................................................................................................................31

Bibliography .............................................................................................................................................................................................................................33

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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.

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 211 Geographic information/Geomatics.

This third edition cancels and replaces the second edition (ISO 6709:2008), which has been technically

revised.
The main changes compared to the previous edition are as follows:
— Harmonization with other recently revised ISO/TC 211 standards

— Clarification of normative requirements to maintain rigid backwards compatibility when required

— Correction of the issues contained in the 2009 Technical Corrigendum to ISO 6709:2008

— Correction of annexes that contained normative requirements but were labelled as informative

— Deletion of annexes and concepts which have changed and were no longer suitable for the

revised edition

— Correction of instances where European numeric formatting conventions were incorrectly inserted

during pre-publication editing. These conventions will no longer be recommended
— Clarification of editorial issues

Annex E presents detailed information on the differences between this and previous editions of

ISO 6709.
Use of numeric formatting conventions:

In accordance with the ISO/IEC Directives, Part 2, 2018, Rules for the structure and drafting of

International Standards, in International Standards the decimal sign is a comma on the line. However,

the General Conference on Weights and Measures (Conférence Générale des Poids et Mesures) at its

meeting in 2003 passed unanimously the following resolution:
“The decimal marker shall be either a point on the line or a comma on the line.”
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In practice, the choice between these alternatives depends on customary use in the language concerned.

In the technical areas of geodesy and geographic information it is customary for the decimal point

always to be used, for all languages. That practice is used throughout this document.

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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Introduction

Geographic point location (GPL) is the description of a well defined geographic place using a single

coordinate tuple. Efficient interchange of GPL data requires formats which are universally interpretable,

and which allow identification of points on, above and below the earth’s surface. Users in various

disciplines may have different requirements. This is exemplified by the use of degrees and decimal

degrees, as well as the traditional degrees, minutes and seconds, for recording latitude and longitude.

Users may also require various levels of precision and may use latitude and longitude without height.

ISO 6709:1983 defined a specific format representation of latitude and longitude, and optionally

altitude.
ISO 6709:2008 revised the format representation of the 1983 edition by:

— adding the ability to identify the CRS to which coordinates are referenced, without which location is

ambiguous, and

— expanding the use of altitude to allow for any ellipsoidal or gravity-related height or depth.

Since the first edition of this document in 1983, the field of geodesy has undergone significant

technological advances, along with the continued development of other related geodesy and geomatics

standards.

The aim of this edition addresses these new advances and standards and revises the coordinate string

suitable for digital representation (Clause 6) while continuing to support the requirements of the

previous edition (Annex B).

Clause 7 defines a simpler structure for the unambiguous representation of GPL in a human-

readable format.
In addition, a series of Annexes are provided with the following content:

— Annex A (normative) defines the abstract test suite used for conformance testing;

— Annex B (normative) defines the representation of latitude and longitude coordinates that maintain

backwards compatibility with ISO 6709:2008;

— Annex C presents a description and examples of how the position of coordinates can appear

ambiguous without the use of a CRS;

— Annex D presents a table of mathematical precision values of resolution for latitude and longitude;

— Annex E describes the changes in this document from the previous edition of ISO 6709.

Users of this document should be aware of the following options:

a) For all cases where backwards compatibility is not required, this document recommends using

the methods and rules specified in Clause 6, GPL representation, or Clause 7, human-readable GPL

representation;

b) However, in systems and environments where backwards compatibility with the previous edition

of ISO 6709 is required, the methods and rules specified in Annex B may be used.

In addition, when using Annex B, it is recommended that suitable and comprehensive ancillary

documentation, not defined within this document, or in previous editions of ISO 6709, should be

prepared and accompany all instances of geographic point location text strings and human-readable

representations claiming backwards compatibility.
The use of this International Standard:

— establishes an expanded point representation string format supporting the current concepts and

standards of geodesy and geographic information;
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— when required, continues to support the needs of established user communities by maintaining

backwards compatibility with the previous edition of this standard;
— reduces the cost of interchange of data;

— reduces the delay in converting non-standard coding structures in preparation for interchange by

providing advance knowledge of the standard interchange format; and
— provides flexible support for geographic point representation.
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oSIST prEN ISO 6709:2021
DRAFT INTERNATIONAL STANDARD ISO/DIS 6709:2020(E)
Standard representation of geographic point location by
coordinates
1 Scope

This document specifies the representation of latitude and longitude and optionally height or depth

compatible with previous editions of ISO 6709.

This document also supports the representations of other coordinate types and time that may be

associated with those coordinates as defined through one or more coordinate reference systems (CRS).

This document describes a text string of coordinates, suitable for electronic data exchange, for

one point including reference system identification to ensure that the coordinates unambiguously

represent the position of that point. Files containing multiple points with a single common reference

system identification are out of scope. This document also describes a simpler text string structure for

coordinate representation of a point location that is more suitable for human readability.

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 8601-1, Date and time — Representations for information interchange — Part 1: Basic rules

ISO 8601-2, Date and time — Representations for information interchange — Part 2: Extensions

ISO/IEC 8859-1, Information technology — 8-bit single-byte coded graphic character sets — Part 1: Latin

alphabet No. 1
ISO 19111, Geographic information — Referencing by coordinates

ISO 19162, Geographic information — Well-known text representation of coordinate reference systems

3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at http:// www .iso .org/ obp
3.1
accuracy

closeness of agreement between a test result or measurement result and the true value

[SOURCE: ISO 3534-2:2006, 3.1.1, modified – The original notes have been deleted.]

3.2
altitude
height where the chosen reference surface is mean sea level
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3.3
compound coordinate reference system

coordinate reference system using at least two independent coordinate reference systems

Note 1 to entry: Coordinate reference systems are independent of each other if coordinate values in one cannot

be converted or transformed into coordinate values in the other.
[SOURCE: ISO 19111:2019, 3.1.3]
3.4
coordinate
one of a sequence of numbers designating the position of a point

Note 1 to entry: In a spatial coordinate reference system, the coordinate numbers are qualified by units.

[SOURCE: ISO 19111:2019, 3.1.5]
3.5
coordinate reference system
coordinate system that is related to an object by a datum

Note 1 to entry: Geodetic and vertical datums are referred to as reference frames.

Note 2 to entry: For geodetic and vertical reference frames, the object will be the Earth. In planetary applications,

geodetic and vertical reference frames may be applied to other celestial bodies.
[SOURCE: ISO 19111:2019, 3.1.9]
3.6
coordinate set

collection of coordinate tuples referenced to the same coordinate reference system and if that

coordinate reference system is dynamic also to the same coordinate epoch
[SOURCE: ISO 19111:2019, 3.1.10]
3.7
coordinate system

set of mathematical rules for specifying how coordinates are to be assigned to points

[SOURCE: ISO 19111:2019, 3.1.11]
3.8
coordinate tuple
tuple composed of coordinates

Note 1 to entry: 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.

[SOURCE: ISO 19111:2019, 3.1.13]
3.9
datum
reference frame

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]
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3.10
depth

distance of a point from a chosen vertical reference surface downward along a line that is perpendicular

to that surface

Note 1 to entry: Note 1 to entry: The line direction may be straight or be dependent on the Earth's gravity field or

other physical phenomena.

Note 2 to entry: Note 2 to entry: A depth above the vertical reference surface will have a negative value.

[SOURCE: ISO 19111:2019, 3.1.17]
3.11
ellipsoidal height
geodetic height

distance of a point from the reference ellipsoid along the perpendicular from the reference ellipsoid to

this point, positive if upwards or outside of the reference ellipsoid

Note 1 to entry: Only used as part of a three-dimensional ellipsoidal coordinate system or as part of a three-

dimensional Cartesian coordinate system in a three-dimensional projected coordinate reference system, but

never on its own.
[SOURCE: ISO 19111:2019, 3.1.24]
3.12
geographic point location
well defined geographic place described by one coordinate tuple
[SOURCE: ISO 19145:2013, 4.1.11]
3.13
geographic point location representation
syntactic description of a geographic point location in a well known format
[SOURCE: ISO 19145:2013, 4.1.12]
3.14
gravity-related height
height that is dependent on the Earth’s gravity field

Note 1 to entry: This refers to, amongst others, orthometric height and Normal height, which are both

approximations of the distance of a point above the mean sea level, but also may include Normal-orthometric

heights, dynamic heights or geopotential numbers.

Note 2 to entry: The distance from the reference surface may follow a curved line, not necessarily straight, as it is

influenced by the direction of gravity.
[SOURCE: ISO 19111:2019, 3.1.37]
3.15
height

distance of a point from a chosen reference surface positive upward along a line perpendicular to

that surface

Note 1 to entry: A height below the reference surface will have a negative value.

Note 2 to entry: Generalisation of ellipsoidal height (h) and gravity-related height (H).

[SOURCE: ISO 19111:2019, 3.1.38]
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3.16
measurement precision
precision

closeness of agreement between indications or measured quantity values obtained by replicate

measurements on the same or similar objects under specified conditions

Note 1 to entry: Measurement precision is usually expressed numerically by measures of imprecision, such as

standard deviation, variance, or coefficient of variation under the specified conditions of measurement.

Note 2 to entry: The "specified conditions" can be, for example, repeatability conditions of measurement,

intermediate precision conditions of measurement, or reproducibility conditions of measurement (see

ISO 5725-3).

Note 3 to entry: Measurement precision is used to define measurement repeatability, intermediate measurement

precision, and measurement reproducibility.

Note 4 to entry: Sometimes "measurement precision" is erroneously used to mean measurement accuracy.

[SOURCE: ISO/IEC Guide 99:2007, 2.15]
3.17
metadata
information about a resource
[SOURCE: ISO 19115-1:2014, 4.10]
3.18
resolution (of a coordinate)
unit associated with the least significant digit of a coordinate

Note 1 to entry: Coordinate resolution may have linear or angular units depending on the characteristics of the

coordinate system.
3.19
sexagesimal degree
angle represented by a sequence of values in degrees, minutes, and seconds

Note 1 to entry: In the case of latitude or longitude, it may also include a character indicating hemisphere.

EXAMPLE 50.0795725 decimal degrees is represented as 50°04'46.461"
3.20
tuple
ordered list of values
Note 1 to entry: The number of values in a tuple is immutable.
[SOURCE: ISO 19136-1:2020, 3.1.60]
4 Abbreviated terms, and changes from the previous edition
4.1 Abbreviated terms
CRS Coordinate Reference System
CRScsd Coordinate Reference System character string delimiter
GPL Geographic Point Location
lat latitude
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lon longitude
URL Uniform Resource Locator
WKT Well-known text
4.2 Character code notations

Bit combinations and Hex values for the character string delimiters required in this document are

represented using abbreviated notation based on ISO/IEC 8859-1, as shown in Table 1.

Table 1 — Character string delimiter bit combinations and Hex codes
8859-1 8859-1
Char- Bit com- Char- Bit com-
Name Hex Name Hex
acter bination acter bination
Code Code
SPACE 02/00 20 RIGHT ANGLE BRACKET > 03/14 3E
QUOTATION MARK " 02/02 22 COMMERCIAL AT @ 00/04 40
APOSTROPHE ' 02/07 27 LATIN CAPITAL LETTER C C 04/03 43
LEFT PARENTHESIS ( 02/08 28 LATIN CAPITAL LETTER E E 04/05 45
RIGHT PARENTHESIS ) 02/09 29 LATIN CAPITAL LETTER H H 04/08 48
PLUS + 02/11 2B LATIN CAPITAL LETTER N N 04/14 4E
HYPHEN MINUS - 02/13 2D LATIN CAPITAL LETTER R R 05/02 52
FULL STOP . 02/14 2E LATIN CAPITAL LETTER S S 05/03 53
SOLIDUS / 02/15 2F LATIN CAPITAL LETTER W 05/07 57
DIGIT ONE 1 03/01 31 LATIN SMALL LETTER D d 06/04 64
DIGIT TWO 2 03/02 32 LATIN SMALL LETTER T t 07/04 74
DIGIT THREE 3 03/03 33 LEFT CURLY BRACKET { 07/11 7B
DIGIT FOUR 4 03/04 34 RIGHT CURLY BRACKET } 07/13 7D
COLON : 03/10 3A DEGREE SIGN ° 11/00 B0
LEFT ANGLE BRACKET < 03/12 3C

EXAMPLE "CRS" is represented by bit combinations 04/03, 05/02, and 05/03 or Hex 43, 52, and 53

respectively.

This document does not specify a required character encoding for GPL string representation or human-

readable notation. However, the use of a widely accepted character encoding such as ISO 8859-1 or

UTF-8 is recommended and should be clearly documented.
4.3 Changes from the previous edition and backwards compatibility

The Foreword of this document provides a brief list of changes from the previous edition. A detailed

presentation of these changes and modifications made to the structure of the document during the

revision process are presented in Annex E. Additionally, the Introduction and Annex E provide an

overview and guidance for using this document. All users are advised to consult these clauses prior to

using the methods and rules specified in this document.

Annex B of this document maintains backwards compatibility with previous editions of ISO 6709.

4.4 Cultural and language adaptability

The previous edition of this document loosely supported cultural and language adaptability by

allowing either a full stop (.) or comma (,) to be used as the "decimal mark." Users must understand

these issues and consult all accompanying metadata and documentation. While the choice between

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these alternatives depends on customary use in the language (locale) concerned, it is preferred, in the

technical areas of geodesy and geographic information that the decimal mark always be a full stop/

decimal point (.) for all languages. That practice is required by this document.
5 Conformance

To conform to this document, representations of GPL shall satisfy the conditions specified in the

abstract test suite (Annex A).
6 Geographic point location representation
6.1 Overview

This edition of ISO 6709 revises and expands the representation of geographic point location (GPL),

while maintaining an option (Annex B) for backwards compatibility with the previous edition

(ISO 6709:2008).

ISO 19111 defines the elements required to describe a coordinate reference system (CRS). A coordinate

tuple represents a location unambiguously only if the CRS to which it is referenced, is identified. Without

this identification, uncertainty in position may result in the location being as much as several hundred

metres distant, see Annex C.

In this edition of ISO 6709, CRS identifiers shall accompany all GPL representations. Identification may

be through:
— a complete URL notation (6.5 a)),
— an abbreviated notation (6.5 b)), or
— a complete CRS definition as specified in ISO 19111 (6.5 c)).

ISO 19111:2019 specifies several CRS types, of which, the following are supported in this document and

any one, or a combination of these, shall accompany all GPL representations:
— geodetic CRS – three-dimensional,
— geographic CRS – two-dimensional or three-dimensional,
— projected CRS – two-dimensional, or sometimes three-dimensional,

— engineering CRS – two-dimensional, or sometimes one-dimensional or three-dimensional,

— parametric CRS – one-dimensional, with normally vertical orientation,
— vertical CRS – one-dimensional,
— temporal CRS – one-dimensional, and
— compound CRS.

NOTE For detailed information about each of these CRS types users should consult ISO 19111:2019.

The text string representation format defined in 6.6 is used for single GPL instances. However, in

practice, GPL instances with uniform representation formats are commonly grouped into coordinate

sets that often provide a single CRS identification f
...