ISO 19162:2019
(Main)Geographic information — Well-known text representation of coordinate reference systems
Geographic information — Well-known text representation of coordinate reference systems
This document defines the structure and content of a text string implementation of the abstract model for coordinate reference systems described in ISO 19111. The string defines frequently needed types of coordinate reference systems and coordinate operations in a self-contained form that is easily readable by machines and by humans. The essence is its simplicity; as a consequence there are some constraints upon the more open content allowed in ISO 19111. To retain simplicity in the well-known text (WKT) description of coordinate reference systems and coordinate operations, the scope of this document excludes parameter grouping and pass-through coordinate operations. The text string provides a means for humans and machines to correctly and unambiguously interpret and utilise a coordinate reference system definition with look-ups or cross references only to define coordinate operation mathematics. A WKT string is not suitable for the storage of definitions of coordinate reference systems or coordinate operations because it omits metadata about the source of the data and may omit metadata about the applicability of the information.
Information géographique — Représentation textuelle bien lisible de systèmes de référence par coordonnées
Geografske informacije - Koordinatni referenčni sistemi, podani kot tekst
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INTERNATIONAL ISO
STANDARD 19162
Second edition
2019-07
Geographic information — Well-
known text representation of
coordinate reference systems
Information géographique — Représentation textuelle bien lisible de
systèmes de référence par coordonnées
Reference number
©
ISO 2019
© ISO 2019
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: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved
Contents Page
Foreword .vi
Introduction .vii
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and abbreviated terms . 1
3.1 Terms and definitions . 1
3.2 Abbreviated terms .10
4 Conformance requirements .10
5 Backus-Naur Form notation and syntax .11
6 WKT string form .12
6.1 Overview .12
6.2 Encoding .12
6.3 Characters used in WKT .12
6.3.1 Basic characters .12
6.3.2 Numbers .13
6.3.3 Date and time .14
6.3.4 CRS WKT characters .15
6.3.5 Double quote .15
6.4 Delimiter .15
6.5 Case sensitivity .16
6.6 Reserved keywords .16
6.7 Backward compatibility .18
7 WKT representation of common attributes .18
7.1 General .18
7.2 Name .18
7.3 Scope, extent, identifier and remark .19
7.3.1 General.19
7.3.2 Usage (scope and extent) .19
7.3.3 Identifier .22
7.3.4 Remark .23
7.4 Unit and unit conversion factor .24
7.4.1 Unit description .24
7.4.2 Conversion factor — Spatial and parametric units .25
7.4.3 Conversion factor — Temporal quantities.25
7.4.4 Default unit .26
7.5 Coordinate system .26
7.5.1 Syntax .26
7.5.2 Coordinate system type, dimension and coordinate data type .29
7.5.3 Axis name and abbreviation .29
7.5.4 Axis direction .30
7.5.5 Axis order .31
7.5.6 Axis unit and coordinate system unit .32
7.5.7 Examples of WKT describing coordinate systems .33
7.6 Datum ensemble .34
7.7 Dynamic coordinate reference systems .36
8 WKT representation of geodetic and geographic coordinate reference systems .37
8.1 Overview .37
8.2 Geodetic reference frame (geodetic datum) . .38
8.2.1 Ellipsoid .38
8.2.2 Prime meridian .39
8.2.3 Geodetic reference frame (datum) .40
8.3 Coordinate systems for geodetic and geographic CRSs .41
8.4 Examples of WKT describing a geodetic or geographic CRS .42
9 WKT representation of projected CRSs .43
9.1 Overview .43
9.2 Base CRS .43
9.2.1 General.43
9.2.2 Ellipsoidal CS unit .44
9.3 Map projection .45
9.3.1 Introduction .45
9.3.2 Map projection name and identifier .46
9.3.3 Map projection method .46
9.3.4 Map projection parameter .47
9.4 Coordinate systems for projected CRSs .47
9.5 Examples of WKT describing a projected CRS .47
10 WKT representation of vertical CRSs .49
10.1 Overview .49
10.2 Vertical reference frame (vertical datum) .50
10.3 Vertical coordinate system .50
10.4 Example of WKT describing a vertical CRS.51
11 WKT representation of engineering CRSs .51
11.1 Overview .51
11.2 Engineering datum .51
11.3 Coordinate systems for engineering CRSs .52
11.4 Examples of WKT describing an engineering CRS .
...
INTERNATIONAL ISO
STANDARD 19162
Second edition
2019-07
Geographic information — Well-
known text representation of
coordinate reference systems
Information géographique — Représentation textuelle bien lisible de
systèmes de référence par coordonnées
Reference number
©
ISO 2019
© ISO 2019
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: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved
Contents Page
Foreword .vi
Introduction .vii
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and abbreviated terms . 1
3.1 Terms and definitions . 1
3.2 Abbreviated terms .10
4 Conformance requirements .10
5 Backus-Naur Form notation and syntax .11
6 WKT string form .12
6.1 Overview .12
6.2 Encoding .12
6.3 Characters used in WKT .12
6.3.1 Basic characters .12
6.3.2 Numbers .13
6.3.3 Date and time .14
6.3.4 CRS WKT characters .15
6.3.5 Double quote .15
6.4 Delimiter .15
6.5 Case sensitivity .16
6.6 Reserved keywords .16
6.7 Backward compatibility .18
7 WKT representation of common attributes .18
7.1 General .18
7.2 Name .18
7.3 Scope, extent, identifier and remark .19
7.3.1 General.19
7.3.2 Usage (scope and extent) .19
7.3.3 Identifier .22
7.3.4 Remark .23
7.4 Unit and unit conversion factor .24
7.4.1 Unit description .24
7.4.2 Conversion factor — Spatial and parametric units .25
7.4.3 Conversion factor — Temporal quantities.25
7.4.4 Default unit .26
7.5 Coordinate system .26
7.5.1 Syntax .26
7.5.2 Coordinate system type, dimension and coordinate data type .29
7.5.3 Axis name and abbreviation .29
7.5.4 Axis direction .30
7.5.5 Axis order .31
7.5.6 Axis unit and coordinate system unit .32
7.5.7 Examples of WKT describing coordinate systems .33
7.6 Datum ensemble .34
7.7 Dynamic coordinate reference systems .36
8 WKT representation of geodetic and geographic coordinate reference systems .37
8.1 Overview .37
8.2 Geodetic reference frame (geodetic datum) . .38
8.2.1 Ellipsoid .38
8.2.2 Prime meridian .39
8.2.3 Geodetic reference frame (datum) .40
8.3 Coordinate systems for geodetic and geographic CRSs .41
8.4 Examples of WKT describing a geodetic or geographic CRS .42
9 WKT representation of projected CRSs .43
9.1 Overview .43
9.2 Base CRS .43
9.2.1 General.43
9.2.2 Ellipsoidal CS unit .44
9.3 Map projection .45
9.3.1 Introduction .45
9.3.2 Map projection name and identifier .46
9.3.3 Map projection method .46
9.3.4 Map projection parameter .47
9.4 Coordinate systems for projected CRSs .47
9.5 Examples of WKT describing a projected CRS .47
10 WKT representation of vertical CRSs .49
10.1 Overview .49
10.2 Vertical reference frame (vertical datum) .50
10.3 Vertical coordinate system .50
10.4 Example of WKT describing a vertical CRS.51
11 WKT representation of engineering CRSs .51
11.1 Overview .51
11.2 Engineering datum .51
11.3 Coordinate systems for engineering CRSs .52
11.4 Examples of WKT describing an engineering CRS .
...
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