Best Practices | OGC

Open GIS Consortium Inc.
Date: 2002-09-24
Reference number of this OpenGIS© project document:

OGC 02-007r4
Version: 0.9.1

Category: OpenGIS© Recommendation Paper
Editor: John Bobbitt

OpenGIS© Recommendation Paper —
Units of Measure Use and Definition Recommendations

OGC 02-007r4

Copyright notice
Copyright 2002 Petrotechnical Open Software Consortium, Inc
Copyright 2002 Open GIS Consortium, Inc
This document is based on material taken from the Units of Measure Recommendation Document,
http://www.posc.org/ComponentDocs/uomFinalRecs.doc
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ii

OpenGIS© Publicly Available Document
Recommendation Paper
Final
English
© OGC 2002 – All rights reserved

OGC 02-007r4

Contents
i.

Preface ................................................................................................................... iv

ii.

Author ................................................................................................................... iv

Foreword ............................................................................................................................ v
Introduction ...................................................................................................................... vi
1

Scope....................................................................................................................... 7

2
2.1
2.2

Conventions............................................................................................................ 7
Symbols (and abbreviated terms) ........................................................................ 7
XML use conventions............................................................................................ 7

3
3.1
3.2
3.3
3.4

Using a unit of measure ........................................................................................ 8
Introduction ........................................................................................................... 8
Abbreviation for units of measure....................................................................... 8
Measure data type ................................................................................................. 8
Unit of measure reference type ............................................................................ 9

4
4.1
4.2
4.3
4.4
4.5
4.6
4.7
4.7.1

Defining a unit of measure.................................................................................... 9
UOM value reference ............................................................................................ 9
UOM reference by symbol.................................................................................. 10
Remote reference data type................................................................................ 10
Defining meaning of a unit of measure.............................................................. 11
Definition of a base unit ...................................................................................... 11
Definition of unit of measure that is not a base unit ........................................ 11
Angular measure ................................................................................................. 12
Implementation of the dms element .................................................................. 13

5

Terms and definitions ......................................................................................... 14

Bibliography .................................................................................................................... 16

© OGC 2002 – All rights reserved

iii

OGC 02-007r4

i.

Preface
This document is a public OGC Recommendation Paper, providing recommendations for
use and definition of the units of measure used for numerical quantities. The
recommendations take the form of Best Practices.

ii.

Author

Name:

John Bobbitt

Address:

Petrotechnical Open Software Corporation
9801 Westheimer, Suite 450
Houston, Texas 77042

Phone:

713-267-5174

Email:

bobbitt@posc.org

iv

© OGC 2002 – All rights reserved

OGC 02-007r4

Foreword
This recommendation paper provides recommendations for use and definition of the units
of measure used for numerical quantities.
Many of these recommendations are stated using XML and XML Schema. The concepts
of use are still valid when not using XML. The implementation, of course, will be
different.
This document partially replaces OGC Discussion Paper 01-044r2: Units of Measure and
Quantity Datatypes. This document contains a listing of the main recommendations.
Attention is drawn to the possibility that some elements of this document may be the
subject of patent rights. The Open GIS Consortium Inc. shall not be held responsible for
identifying any or all such patent rights.

© OGC 2002 – All rights reserved

v

OGC 02-007r4

Introduction
The basic information needed to understand a measured value is the value and the unit of
measure. Eight different ways, and various options of these ways, to tie these two pieces
of information were identified. The goal of this project was to develop a preferred way to
implement this information in XML.
In addition, it was noted that a symbol for a unit of measure was not sufficient to identify
it. Thus, this recommendation paper also defines a best practice for giving the meaning of
a unit of measure.

vi

© OGC 2002 – All rights reserved

OGC 02-007r4

OpenGIS© Recommendation Paper — Units of Measure Use and
Definition Recommendations

1

Scope

This OpenGIS© Recommendation Paper provides recommendations for use and definition
of the units of measure used for numerical quantities. These recommendations are more
widespread than OpenGIS only, and are being proposed at other organizations, including
POSC, W3C, CSIRO, PIDX, and OASIS.
These recommendations are given as best practices, and are not intended to be rigidly
followed. However, it is recommended that variations from these practices be considered
for their negative effects on interoperability.
The recommendations are stated for a single, measure value. However, many of the same
structures apply to arrays and tuples of values. XML Schema and documents that capture
arrays of values, and tuples of values, should consider the patterns of these
recommendations, and follow them where appropriate.
Many of these recommendations are stated using XML and XML Schema. These
recommendations should be followed even when XML is not being used.
2

Conventions

2.1

Symbols (and abbreviated terms)

ISO

International Organization for Standardization

OGC

Open GIS Consortium

UOM

Unit of Measure

W3C

World Wide Web Consortium

XML

eXtended Markup Language

2.2

XML use conventions

This document uses a set of conventions for use of XML and XML Schema, that
currently include:
a) Use of xsd prefixes to indicate the XML schema elements, as defined in the W3C
proposed recommendation dated 30 March 2001.
b) Snippets of XML being used as examples forgo any use of namespaces.

© OGC 2002 – All rights reserved

7

OGC 02-007r4

3
3.1

Using a unit of measure
Introduction

This clause provides recommendations for using a unit of measure. The use of a unit of
measure is meant to encompass the means by which a measured value is tied explicitly to
its unit of measure.
3.2

Abbreviation for units of measure

Recommendation 1: When an abbreviation for units of measure is to be used in an
element or attribute name, the abbreviation should be uom or UOM.
Comment: The other obvious choice is “unit.” Since “unit” can have other meanings, it
was felt that “uom” was a better choice than “unit.” The important point is to select one,
and use it exclusively.
Comment: This recommendation is for abbreviations only. It is still permissible to use
the full name, “UnitOfMeasure,” where appropriate.
3.3

Measure data type

Recommendation 2: A QuantityType data type should be defined in XML Schema as
follows:

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PENGARUH PENERAPAN MODEL DISKUSI TERHADAP KEMAMPUAN TES LISAN SISWA PADA MATA PELAJARAN ALQUR’AN HADIS DI MADRASAH TSANAWIYAH NEGERI TUNGGANGRI KALIDAWIR TULUNGAGUNG Institutional Repository of IAIN Tulungagung

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PENGARUH PENERAPAN MODEL DISKUSI TERHADAP KEMAMPUAN TES LISAN SISWA PADA MATA PELAJARAN ALQUR’AN HADIS DI MADRASAH TSANAWIYAH NEGERI TUNGGANGRI KALIDAWIR TULUNGAGUNG Institutional Repository of IAIN Tulungagung

40 1057 43

PENGARUH PENERAPAN MODEL DISKUSI TERHADAP KEMAMPUAN TES LISAN SISWA PADA MATA PELAJARAN ALQUR’AN HADIS DI MADRASAH TSANAWIYAH NEGERI TUNGGANGRI KALIDAWIR TULUNGAGUNG Institutional Repository of IAIN Tulungagung

40 945 23

PENGARUH PENERAPAN MODEL DISKUSI TERHADAP KEMAMPUAN TES LISAN SISWA PADA MATA PELAJARAN ALQUR’AN HADIS DI MADRASAH TSANAWIYAH NEGERI TUNGGANGRI KALIDAWIR TULUNGAGUNG Institutional Repository of IAIN Tulungagung

21 632 24

PENGARUH PENERAPAN MODEL DISKUSI TERHADAP KEMAMPUAN TES LISAN SISWA PADA MATA PELAJARAN ALQUR’AN HADIS DI MADRASAH TSANAWIYAH NEGERI TUNGGANGRI KALIDAWIR TULUNGAGUNG Institutional Repository of IAIN Tulungagung

28 790 23

KREATIVITAS GURU DALAM MENGGUNAKAN SUMBER BELAJAR UNTUK MENINGKATKAN KUALITAS PEMBELAJARAN PENDIDIKAN AGAMA ISLAM DI SMPN 2 NGANTRU TULUNGAGUNG Institutional Repository of IAIN Tulungagung

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KREATIVITAS GURU DALAM MENGGUNAKAN SUMBER BELAJAR UNTUK MENINGKATKAN KUALITAS PEMBELAJARAN PENDIDIKAN AGAMA ISLAM DI SMPN 2 NGANTRU TULUNGAGUNG Institutional Repository of IAIN Tulungagung

66 1253 50

KREATIVITAS GURU DALAM MENGGUNAKAN SUMBER BELAJAR UNTUK MENINGKATKAN KUALITAS PEMBELAJARAN PENDIDIKAN AGAMA ISLAM DI SMPN 2 NGANTRU TULUNGAGUNG Institutional Repository of IAIN Tulungagung

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KREATIVITAS GURU DALAM MENGGUNAKAN SUMBER BELAJAR UNTUK MENINGKATKAN KUALITAS PEMBELAJARAN PENDIDIKAN AGAMA ISLAM DI SMPN 2 NGANTRU TULUNGAGUNG Institutional Repository of IAIN Tulungagung

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KREATIVITAS GURU DALAM MENGGUNAKAN SUMBER BELAJAR UNTUK MENINGKATKAN KUALITAS PEMBELAJARAN PENDIDIKAN AGAMA ISLAM DI SMPN 2 NGANTRU TULUNGAGUNG Institutional Repository of IAIN Tulungagung

41 1350 23