Global Positioning System: A Field Guide for the Social Sciences

227 Pages·2003·0.83 MB·English

by  John Spencer, Brian G. Frizzelle, Philip H. Page, John B. Vogler(auth.)

Global Positioning System
Global Positioning
System:
A Field Guide for the
Social Sciences
John Spencer
University of North Carolina
Brian G. Frizzelle
University of North Carolina
Philip H. Page
University of North Carolina
John B. Vogler
East-West Center, Honolulu
© 2003 by John Spencer, Brian G. Frizzelle, Philip H. Page, and John B. Vogler
350 Main Street, Malden, MA 02148-5020, USA
108 Cowley Road, Oxford OX4 1JF, UK
550 Swanston Street, Carlton, Victoria 3053, Australia
The right of John Spencer, Brian G. Frizzelle, Philip H. Page, and John B. Vogler to
be identified as the Authors of this Work has been asserted in accordance with the
UK Copyright, Designs, and Patents Act 1988.
All rights reserved. No part of this publication may be reproduced, stored in a re-
trieval system, or transmitted, in any form or by any means, electronic, mechanical,
photocopying, recording or otherwise, except as permitted by the UK Copyright,
Designs, and Patents Act 1988, without the prior permission of the publisher.
First published 2003 by Blackwell Publishing Ltd
Library of Congress Cataloging-in-Publication Data
Global Positioning System : a field guide for the social sciences / John
Spencer . . . [et al.].
p. cm.
Includes bibliographical references and index.
ISBN 1–4051–0184–9 (hardback : alk. paper) — ISBN 1–4051–0185–7
(pbk. : alk. paper)
1. Global Positioning System. I. Spencer, John.
G109.5 .G56 2003
910¢.285—dc21 2002152561
ISBN 1-4051-0184-9 (hardback); ISBN 1-4051-0185-7 (paperback)
A catalogue record for this title is available from the British Library.
Set in 10.5 on 12.5 Times
by Ace Filmsetting Ltd, Frome, Somerset
Printed and bound in the United Kingdom
by MPG Books Ltd, Bodmin, Cornwall
For further information on
Blackwell Publishing, visit our website:
http://www.blackwellpublishing.com
Contents
List of Figures vii
List of Tables x
Acknowledgments xi
1 Introduction 1
Part I Understanding GPS 7
2 Why use GPS? 9
3 What is GPS? 26
4 Coordinate Systems and Datums 34
5 GPS Considerations: Getting Started 50
Part II Utilizing GPS 71
6 Developing a GPS Project 73
7 Project Fundamentals 76
8 Fieldwork Planning and Preparations: Data and Methods 89
9 Fieldwork Planning and Preparations: Field Resources 113
10 Fieldwork Planning and Preparations: Data Quality and
Logistics 133
11 Transitioning to Fieldwork 146
12 Post-Fieldwork Processing 170
vi CONTENTS
13 Utilizing GPS Data within Geographic Information Systems 179
14 Conclusion 196
References 204
Appendix A GPS Manufacturers 208
Appendix B Sample Field Instrument 209
Appendix C UTM Zones 212
Index 214
Figures
2.1. A comparison of a geocoded address and absolute GPS
location 24
3.1. The GPS satellite constellation consists of 28 satellites
orbiting 12,500mi above the Earth in orbital planes designed
to keep at least four satellites above the horizon anywhere
on the planet 28
3.2. The captain determines the ship’s location by measuring
distances (based on time) from three lighthouse foghorns.
(a) One measurement puts the ship somewhere on a circle.
(b) Two measurements reduce the possible locations to two
points where the circles intersect. (c) Three measurements
determine a single location 31
3.3. (a) The ranges from three incorrect clocks won’t intersect at
a single point. (b) The error can be removed by adjusting
the clock timing until the three circles converge on a single
point 33
4.1. Geodetic latitudes and longitudes specify locations on a
reference ellipsoid 36
4.2. A simplified representation of a local geodetic datum. The
datum provides a link between geodetic coordinates on the
ellipsoid and actual locations on the Earth. (Differences
between the ellipsoid and the Earth’s surface are exaggerated) 39
4.3. Map projections make it possible for us to map the three-
dimensional world in two dimensions 43
viii FIGURES
4.4. Cylindrical, planar, and conic developable surfaces 43
4.5. Projected, two-dimensional Cartesian coordinate systems
are used for most mapping and GIS applications 44
4.6. The Universal Transverse Mercator (UTM) system divides the
globe into 60 zones. Within each zone there are two coordinate
systems, one north of the Equator and one south 46
4.7. Each US state is divided into one or more zones in the State
Plane Coordinate System (SPCS). Each zone has an origin
to its south and east 48
5.1. Buildings and other solid objects may deflect the satellite
signals, resulting in multipath interference 54
5.2. Positional dilution of precision (PDOP) is a multiplicative
error caused by satellite geometry 55
8.1. Higher dimension spatial objects created from point locations 99
8.2. Slope distance vs. planimetric distance in augmented
coordinate derivations 105
9.1. Suggested fields to use when designing forms
incorporating GPS data collection 124
9.2. Example of a ground control data collection form for a
series of aerial photographs 126
9.3. Example of a data collection form for recording health facility
locations and selected attributes in cities and towns within
a study area 127
10.1. Sample project timeline detailing benchmarks in fieldwork
planning, fieldwork, and post-fieldwork phases 142
11.1. Sample outline for a GPS data collection training manual
and training course syllabus 154
13.1. Vector point, line, and polygon features. Each feature has
a corresponding record in an attribute database 182
13.2. An attribute value is stored for each cell in a raster map layer 183
13.3. (a) Point map showing locations of violent robbery crime
events. (b) The same map but with map layers containing
locations of paycheck cashing and instant-loan businesses
displayed as well 184
FIGURES ix
13.4. A point-in-polygon overlay can attach contextual
socioeconomic data from census enumeration units to
GPS point locations of households 186
13.5. Overlaying polygon and raster map layers to generate
information about the environmental conditions
surrounding communities 187
13.6. Recreational facilities and spatial buffers around urban
households 188
13.7. The nearest market location to each household, based on
Euclidean distance 189
13.8. The nearest market locations to households, based on
network distance 190
13.9. Standard distance plotted on (a) clustered and (b)
dispersed point data 191
13.10. Spatially clustered, random, and regular distributions of
point data 193
Tables
2.1. Scale-dependent errors, based on the US national map
accuracy standards 21
5.1. Error source contributions 56
5.2. Some popular map scales and the compatible positioning
methods with estimated costs 67
8.1. Equations for deriving augmented geographic coordinates 104
9.1. Example of a simple data dictionary for describing selected
attributes of rural communities in a study region 128
Acknowledgments
This book represents the cumulative experience and knowledge of the au-
thors as learned in the classroom and in the field. However, as with any
learning process, there were many people along the way that served as men-
tors and guides. They helped us learn what should be done, what works and
what doesn’t, and each made a unique contribution that taught us a valuable
lesson or provided guidance. There are two key people in particular the
authors would like to collectively thank. Stephen J. Walsh from the Depart-
ment of Geography at the University of North Carolina, Chapel Hill was
instrumental in giving all of us the opportunity to develop our GPS and GIS
skills either in the classroom, in the field or on the job.
Steve McGregor was the Associate Director for Spatial Analysis at the
Carolina Population Center at the University of North Carolina, Chapel
Hill. For the three of us who had the chance to work with him, he taught us
many valuable lessons, including the importance of proper planning, proper
GPS usage, and high quality in our work.
Through our work at the University of North Carolina, we have had op-
portunities to work with research fellows at the Carolina Population Center
and faculty in the Department of Geography. Working with the following
people gave us a chance to hone our skills and hopefully contribute to their
research: Gustavo Angeles, Dick Bilsborrow, Ties Boerma, Barbara
Entwisle, Wil Gesler, Ron Rindfuss, Amy Tsui, and Sharon Weir.
Individually, the authors would also like to thank the following people:
John Spencer: I would like to thank my parents for a lifetime of support
and encouragement. Geoff Fuller gave extremely valuable assistance and
counsel on the publishing world and was very instrumental in walking us
through the process of finding a publisher. I don’t know if this book would
have happened at all without his advice. Brad Hutchinson, Jill Sunderlin,
and Jill Sherman all reviewed drafts of chapters and gave many helpful