The Global Positioning Systemand GIS: An Introduction Second Edition The Global Positioning System and GIS: An Introduction Second Edition Featuring hardware and GPS software from Trimble Navigation, Limited, and GIS software from Environmental Systems Research Institute (ESRI) Michael Kennedy University of Kentucky London and New York First published 1996 by Ann Arbor Press Second edition 2002 by Taylor & Francis 11 New Fetter Lane, London EC4P 4EE Simultaneously published in the USA and Canada by Taylor & Francis Inc, 29 West 35th Street, New York, NY 10001 Taylor & Francis is an imprint of the Taylor & Francis Group This edition published in the Taylor & Francis e-Library, 2005. “To purchase your own copy of this or any of Taylor & Francis or Routledge’s collection of thousands of eBooks please go to www.eBookstore.tandf.co.uk.” © 2002Taylor & Francis All rights reserved. No part of this book may be reprinted or reproduced or utilised in any form or by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying and recording, or in any information storage or retrieval system, without permission in writing from the publishers. Every effort has been made to ensure that the advice and information in this book is true and accurate at the time of going to press. However, neither the publisher nor the authors can accept any legal responsibility or liability for any errors or omissions that may be made. In the case of drug administration, any medical procedure or the use of technical equipment mentioned within this book, you are strongly advised to consult the manufacturer’s guidelines. ESRI™, ArcInfo™, ArcView™, ArcUSA™, and Arc World™ are registered trademarks of the Environmental Systems Research Institute of Redlands, CA, USA. Windows™ is a registered trademark of Microsoft, Inc. of Seattle, WA, USA. GeoExplorer™, Pathfinder Office™, GPS Pathfinder™, and PFINDER™ are registered trademarks of Trimble Navigation, Ltd., Sunnyvale, CA, USA. All other brand names are trademarks of their respective holders. British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library Library of Congress Cataloging in Publication Data A catalog record for this book has been requested ISBN 0-203-30106-4 Master e-book ISBN ISBN 0-203-34551-7 (Adobe eReader Format) ISBN 0-415-28608-5 (Print Edition) for Alexander Kennedy ABOUT THE AUTHOR Michael Kennedy’s involvement with Geographic Information Systems (GIS) began in the early 1970s with his participation on a task force formed by the Department of the Interior to provide technical recommendations for pending federal land use legislation. In the mid-1970s he and coauthors wrote two short books on GIS, both published by the Urban Studies Center at the University of Louisville where he was enjoying sabbatical leave from the University of Kentucky. SpatialInformation Systems: An Introduction with Charles R.Meyers is a description of the components of a GIS and was a guide to building one at the time when there was no off-the-shelf software. Avoiding System Failure:Approaches to Integrity and Utility with Charles Guinn described potential pitfalls in the development of a GIS. With Mr. Meyers and R.Neil Sampson he also wrote the chapter “Information Systems for Land Use Planning” forPlanning the Uses and Management of Land, a monograph published in 1979 by the American Society of Agronomy. Professor Kennedy is also a computer textbook author, having cowritten, with Martin B.Solomon, Ten Statement Fortran Plus Fortran IV, Structured PL/ZERO Plus PL/ONE, and Program Development with TIPS andStandard Pascal, all published by Prentice-Hall. Over the years Professor Kennedy has had a wide range of experiences relating computers and environmental matters. Primarily to be able to talk to planners about the newly emerging field of GIS he became certified as a planner by the American Institute of Certified Planners (AICP). He was Director of the Computer-Aided Design Laboratory at the University of Kentucky for several years. He has been invited to vi teach GIS and/or programming at Simon Fraser University and several state or provincial universities: North Carolina, Florida, and British Columbia. Outside of his interest in the Global Positioning System (GPS) the author’s primary concern is in the development of computer data structures for the storage of geographic information. In work sponsored by the Ohio State University Center for Mapping and the Environmental Systems Research Institute, he is currently developing what he calls the dot-probability paradigm for the storage of spatial data. Fundamentally, the author is a programmer who has sought out the application of computers to environmental issues. He is currently an Associate Professor in the Geography Department at the University of Kentucky, where he teaches GIS and GPS. CONTENTS Foreword to the First Editionxviii Foreword to the Second Edition xxi Preface for the Instructorxxiii Acknowledgments xxix Introductionxxxiv Chapter 1– Basic Concepts 1 Overview 1 Where Are You? 2 What Time Is It? 4 GPS and GIS 4 Anatomy of the Term: “Global Positioning 6 System” The Earth 7 Earth-Circling Satellites 7 Ground-Based Stations 9 Receivers 10 Receiver Manufacturers 11 The United States Department of Defense 11 Users 12 How We Know Where Something Is 12 Step-By-Step 17 Disclaimer 17 Preparation 17 viii Project 1A 17 Getting Acquainted with a GPS Receiver 17 Power On and Off 20 The Sources of Power and Other Gadgets 22 Understanding the Screens and Controls 24 Setting Vital Parameters 29 Preparing to Correlate GPS Data with Map 32 Data Double-Checking the Configuration 34 Final Inside Activity 34 Project 1B 35 Now Outside 35 Tracking Satellites 36 Set Your Watch 40 Did the Earth Move? 40 Project 1C 42 Back Inside 42 The Shape of the Earth–Finding Elevations 42 Compare the Two Altitude Referencing 43 Systems The Datum Makes a Difference 45 Latitude Computation Based on the Single 48 “Old” Position Longitude Computation Based on the Single 49 “Old” Position GPS Equipment Checkout Form 50 Chapter 2– Automated Data Collection 51 Overview 51 How’d They Do That? 51 ix How It Works: Measuring Distance by 54 Measuring Time Factors Affecting When and How to Collect 59 Data Position Accuracy and DOP 60 So, Actually, What is DOP? 62 Step-By-Step 64 Project 2A 64 Inside: Planning the GPS Data Collection 64 Session Setting up the Receiver/Datalogger 65 In the Field: Collecting Data 71 Project 2B 72 Taking Data Along a Path 72 Taking Data on Foot 74 Collecting Data by Bicycle 74 Collecting Data by Automobile 75 Actual Data Collection 76 Project 2C 77 Back Inside 77 Execute the Pathfinder Office Software 78 Exercise–Transfer the Almanac 85 Data Collection Parameter Form–GPS2GIS 87 Chapter 3– Examining GPS Data 88 Overview 88 Some Questions Answered 88 Step-By-Step 97 Project 3A–Volcano 97 Explore the Map 101 x Examine Properties of GPS Fixes 105 Looking at More Detail 106 Manipulating Files 107 Project 3B–Rooftop I 111 Project 3C–New Circle Road 115 Project 3D–SA Goes Away–Background Files 118 Help You See It An Aerial Photo That Can Be Used as a Map: 119 The Digital Orthophoto Project 3E–Your Data 121 Exercises 126 Chapter 4– Differential Correction 130 Overview 130 GPS Accuracy in General 130 Differential Correction in Summary 130 Thinking about Error 131 First Line of Defense against Error: 132 Averaging Sources of GPS Error 133 Clock Errors 134 Ephemeris Errors 134 Receiver Errors 134 Atmospheric Errors 135 Multipath Errors 135 Selective Availability–A Former (We Hope) 136 Source of Error Reducing Errors 136 More Formally 138 Making Differential Correction Work 141 Proof of the Pudding 143 xi Step-By-Step 144 Project 4A–Rooftop II 144 Look at the Effects of Differential Correction 144 Project 4B–The McVey Monument 147 Correct Some Supplied Point Data 147 Map the Data 151 Project 4C–McVey Waypoint 152 Waypoints–Using One to Check Your Work 152 Make a Waypoint in Pathfinder Office 153 Project 4D–Vancouver 155 Look at Some Corrected Line Data 155 Project 4E 159 Differentially Correct Some Supplied Line 159 Data– New Circle Road Again Differential Correction Also Improves GPS 161 Accuracy with SA Off Project 4F–The UK Campus 163 More GPS Files and DOQs 163 Correct the Rover File 165 Correct a Base Station File 166 Look at a High Resolution Color DOQ 169 Project 4G–DOP Matters 170 Project 4H–Your Data II 170 Correct Your Own Data 170 Exercises 173 Community Base Stionat Information Form 175 Chapter 5– ArcView, ArcData, and GPS 176 Overview 176 What GIS Is 176 xii GPS and GIS 177 ESRI GIS Products and Terminology 177 We Start with ArcView 178 Integration of GIS Activities 179 The Components of ArcView 179 Views 181 Operations on Themes and Views 182 The ArcUSA Database 182 Step-By-Step 183 Project 5-A 183 Seeing GPS Data with ArcView 183 Starting Arc View 184 Getting Help 185 Starting a New Project…and Saving It 186 Opening a Project 188 Initiating a View 189 Views and Coverages: Adding a GPS-Based 189 Theme Editing the Legend 190 Projecting Coordinates 191 Adding a Theme from ArcUSA 195 Identifying Particular Features of a 197 Particular Theme Magnifying and Moving the Graphic Image 198 Selecting Features 199 Adding Water 200 Bringing Up a Theme Table 201 Making Queries, and Looking at Text and 201 Graphics xiii More Complex Selecting 204 Other Cool Table Operations 205 Exercises 206 Chapter 6– Integrating GPS Data with GIS Data 212 Overview 212 Reviewing What You Know 213 Prescription