ddeenn4433882233__ffmm__ii--xxvvii..iinndddd PPaaggee ii 77//1177//0088 88::3377::2277 PPMM uusseerr--ss117744 //VVoolluummeess//220022//MMHHDDQQ002222//mmhhddeenn66//ddeenn66ffmm SIXTH EDITION CARTOGRAPHY Thematic Map Design BORDEN D. DENT Georgia State University JEFFREY S. TORGUSON St. Cloud State University THOMAS W . HODLER University of Georgia ddeenn4433882233__ffmm__ii--xxvvii..iinndddd PPaaggee iiii 77//1188//0088 1111::4444::4400 PPMM uusseerr--ss220066 //VVoolluummeess//220022//MMHHDDQQ002222//mmhhddeenn66//ddeenn66ffmm CARTOGRAPHY: THEMATIC MAP DESIGN, SIXTH EDITION Published by McGraw-Hill, a business unit of The McGraw-Hill Companies, Inc., 1221 Avenue of the Americas, New York, NY 10020. Copyright © 2009 by The McGraw-Hill Companies, Inc. All rights reserved. Previous editions © 1999, 1996, 1993, 1990, and 1985. No part of this publication may be repro- duced or distributed in any form or by any means, or stored in a database or retrieval system, without the prior written consent of The McGraw-Hill Compa- nies, Inc., including, but not limited to, in any network or other electronic storage or transmission, or broadcast for distance learning. Some ancillaries, including electronic and print components, may not be available to customers outside the United States. This book is printed on recycled, acid-free paper containing 10% postconsumer waste. 1 2 3 4 5 6 7 8 9 0 QPD/QPD 0 9 8 ISBN 978–0–07–294382–5 MHID 0–07–294382–3 Publisher: Thomas Timp Executive Editor: Margaret J. Kemp Director of Development: Kristine Tibbetts Senior Developmental Editor: Joan M. Weber Senior Marketing Manager: Lisa Nicks Project Coordinator: Mary Jane Lampe Lead Production Supervisor: Sandy Ludovissy Senior Designer: David W. Hash Cover/Interior Designer: Ellen Pettergell Cover Illustration: Map courtesy Reynolds et al., Exploring Geology, 2008. Data from Hargrove, W. and F. Hoffman, 2004, “The potential of multivariate quantitative methods for delineation and visualization of ecoregions,” Environmental Management 34(5): S39–S60. Lead Photo Research Coordinator: Carrie K. Burger Compositor: Aptara®, Inc. Typeface: 10/12 Times Printer: Quebecor World Dubuque, IA Library of Congress Cataloging-in-Publication Data Dent, Borden D. Cartography : thematic map design/Borden D. Dent, Jeffrey S. Torguson, Thomas W. Hodler.—6th ed. p. cm. Includes index. ISBN 978–0–07–294382–5—ISBN 0–07–294382–3 (hard copy : alk. paper) 1. Cartography. 2. Thematic maps. I. Torguson, Jeffrey. II. Hodler, T. W. III. Title. GA105.3.D45 2009 526—dc22 2008025397 www.mhhe.com ddeenn4433882233__ffmm__ii--xxvvii..iinndddd PPaaggee iiiiii 77//1177//0088 88::3377::2288 PPMM uusseerr--ss117744 //VVoolluummeess//220022//MMHHDDQQ002222//mmhhddeenn66//ddeenn66ffmm In memory of Borden D. Dent 1938–2000 teacher and leader in the world of cartography . ddeenn4433882233__ffmm__ii--xxvvii..iinndddd PPaaggee iivv 77//1177//0088 88::3377::2288 PPMM uusseerr--ss117744 //VVoolluummeess//220022//MMHHDDQQ002222//mmhhddeenn66//ddeenn66ffmm ddeenn4433882233__ffmm__ii--xxvvii..iinndddd PPaaggee vv 77//1177//0088 88::3377::2288 PPMM uusseerr--ss117744 //VVoolluummeess//220022//MMHHDDQQ002222//mmhhddeenn66//ddeenn66ffmm CONTENTS About the Authors xi Preface xiii PART I THEMATIC MAPPING ESSENTIALS 1 1 INTRODUCTION TO THEMATIC Coordinate Geometry for the Cartographer 26 Plane Coordinate Geometry 27 MAPPING 2 The Geographic Grid 28 The Realm of Maps 3 Latitude Determination 28 The Map Defi ned 3 Longitude Determination 29 What Is Cartography? 4 The Complete Geographic Grid 30 Geographic Cartography 5 Principal Geometric Relationships of the Earth’s Geographic Grid 30 Atlas Mapping 5 Kinds of Maps 6 Scale Revisited 33 General Purpose Maps 6 Scale and Line Generalization 34 Thematic Maps 7 Map Scale 11 3 MAP PROJECTIONS 37 Modern Views of Map Communication 13 Map Communication and Visualization 13 The Map Projection Process 38 The Importance of Meaning 15 Developable Surfaces 38 Cartography and Geographic Information Systems 16 Projection Parameters 39 Artistic Drawing Programs 16 Projection Families 40 Cartographic Abstraction and Generalization 16 Azimuthal Family 40 Selection 17 Cylindrical Family 41 Classifi cation 17 Conic Family 44 Simplifi cation 17 Mathematical Family 44 Symbolization 17 Map Projection Properties 44 The Art in Cartography 18 Equal Area Mapping 44 Thematic Map Design 18 Conformal Mapping 45 What Is Map Design? 19 Equidistance Mapping 46 Ethics in Cartography 19 Azimuthal Mapping (Direction) 46 Minimum Error Projections 47 Determining Deformation and its Distribution Over the 2 BASIC GEODESY, COORDINATE Projection 47 Standard Lines and Points, Scale Factor 48 SYSTEMS, AND SCALE 23 Employment of Map Projections 49 Basic Geodesy 23 Essential Questions 50 The Size and Shape of the Earth 24 World Projections 50 Datums 26 Mathematical, Equivalent Projections 50 v ddeenn4433882233__ffmm__ii--xxvvii..iinndddd PPaaggee vvii 77//1188//0088 1111::5500::2266 PPMM uusseerr--ss220066 //VVoolluummeess//220022//MMHHDDQQ002222//mmhhddeenn66//ddeenn66ffmm vi CONTENTS Minimum Error Projections 51 Processing Error 75 Cylindrical Projections 52 Cartographic Design Error 75 Projections for Mapping Continents 53 Data Sources 76 Mapping Multiple Size Countries at Mid-Latitudes 55 Data (GIS) Clearinghouses 76 Mapping at Low Latitudes 55 Federal Governmental Agencies 76 Projected Coordinate Systems 56 U.S. Census Bureau 76 State Plane Coordinate (SPC) System 56 U.S. Geological Survey 76 Universal Transverse Mercator (UTM) System 56 Federal Information Processing Standards Adjustments in Projection Parameters 60 (FIPS) 76 Potential Problems 77 4 THE NATURE OF GEOGRAPHIC DATA AND THE SELECTION OF THEMATIC 5 DESCRIPTIVE STATISTICS AND DATA MAP SYMBOLS 63 CLASSIFICATION 80 The Nature of Data 64 Overview of A Data Set 81 Data Characteristics 65 Ratio, Proportion, Percent, and Rate 81 Location 65 Descriptive Statistics 82 Form 66 Skewness 84 Time 67 Kurtosis 85 Data Transformations 68 Data Classifi cation 85 Scale 68 Selection of the Number of Classes 85 Form 68 Nothing Is Sacred 86 Boundary Changes 68 Values of Zero or No Data 86 Data Measurement 69 Impact of the Number of Classes 86 Nominal 69 Data Classifi cation Schemes 86 Ordinal 69 Natural Breaks 87 Interval 69 Nested Means 89 Ratio 70 Mean and Standard Deviation 90 Data: Thematic Map Relationships 70 Equal Interval 90 Map Symbols 70 Equal Frequency 91 Visual Variables 71 Arithmetic and Geometric Intervals 91 Size 71 User Defi ned 92 Shape 71 Assessment Indices 92 Orientation 73 Things to Watch Out For 93 Texture 73 Outliers and Data Truncation 93 Saturation and Value 74 Zero-Observation Classes 94 Cartographic Error 74 Summary and Comparison of Major Classifi cation Source Error 74 Methods 94 PART II TECHNIQUES OF QUANTITATIVE THEMATIC MAPPING 101 6 MAPPING ENUMERATION AND OTHER Data Classifi cation Revisited 106 Classifi cation Methods Compared 108 AREALLY AGGREGATED DATA: THE Data Truncation and Outliers 109 CHOROPLETH MAP 102 Different Maps from the Same Data 109 Selecting The Choropleth Technique 102 Unclassed Choropleth Maps 109 Mapping Rationale 102 Legend Design, Areal Symbolization, And Base Map Appropriateness of Data 104 Design 111 When to Use the Choropleth Map 105 Sources of Map-Reading Error and the Need for Accurate Preliminary Considerations in Choropleth Mapping 105 Design Response 111 Geographic Phenomena 105 Legend Design 111 Map Scale 105 Box Shape, Size, Orientation, and Number and Kinds of Enumeration Units 106 Range Placement 111 Data Processing 106 Continuous and Noncontinuous Class Ranges 112 ddeenn4433882233__ffmm__ii--xxvvii..iinndddd PPaaggee vviiii 77//1199//0088 22::5599::0077 AAMM uusseerr--ss220088 //VVoolluummeess//220022//MMHHDDQQ002222//mmhhddeenn66//ddeenn66ffmm CONTENTS vii Class Range Formatting, Legend Titles, and Other Legend Bivariate and Multivariate Proportional Symbols 147 Information 112 Overloaded Proportional Point Symbols 147 Map Sequences and Animated Maps Considerations 113 Proportional Symbols and Choropleth Maps 148 Symbolization for Choropleth Maps 113 Black and White Mapping 113 Color Map Symbolization 114 9 MAPPING GEOGRAPHIC SURFACES: Bipolar and Bivariate Symbolization 115 ISARITHMIC AND THREE-DIMENSIONAL Adding Other Reference Features to the Map 115 MAPS 150 Dasymetric Mapping 116 The Nature of Isarithmic and Three-Dimensional Mapping 150 7 THE DOT DENSITY MAP 119 Fundamental Concepts 150 Isarithmic Categories and Terminology 151 Mapping Technique 119 The Basis of Isarithmic Construction 152 Advantages and Disadvantages of Dot Density A Brief History of Isarithmic Mapping 154 Mapping 120 When to Select the Isarithmic Method 155 Data Suitability 121 Isarithmic Practices 155 The Mapping Activity 122 Elements of Isarithmic Mapping 155 Size of Enumeration Unit 124 Concepts in Isarithm Placement 155 Dot Value and Size 125 Locating Data Points 155 Dot Placement 126 Concept of Interpolation 156 Legend Design 127 Automated Isarithmic Mapping 157 Other Dot Map Design Issues 128 Gridding Methods of Interpolation 158 Visual Impressions of Dot Maps: Questions of Evaluating Grid Error 159 Numerousness And Density 129 The Selection of Isarithmic Intervals 160 Other Presentations of Continuous Surfaces 162 Shaded Relief Maps 162 8 FROM POINT TO POINT: Wireframe and Surface Maps 162 Communicating Using Multiple Map THE PROPORTIONAL SYMBOL MAP 131 Displays 163 Conceptual Basis For Proportional Point Symbol Design Aspects For Isarithmic and Continuous Mapping 131 Surface Maps 164 When to Select this Method—Data Suitability 131 Isolines and Figure-Ground Relationship 164 A Brief History of Proportional Point Symbols 133 Isoline Labels 164 A Variety of Symbol Choices 133 Legend Design 165 Two-Dimensional Geometric Symbols 133 Other Useful Elements 166 Three-Dimensional Geometric Symbols 134 Pictorial Symbols 135 10 THE CARTOGRAM: VALUE-BY-AREA Proportional Symbol Scaling 136 MAPPING 168 Absolute and Apparent Magnitude Scaling: Psychophysical Examination of Quantitative The Value-By-Area Cartogram Defi ned 168 Thematic Map Symbols 137 Brief History of the Method 170 Absolute Scaling with Circles 137 Two Basic Forms Emerge 171 Apparent Magnitude Scaling with Circles 139 Contiguous Cartograms 171 The Square Symbol 141 Noncontiguous Cartograms 172 Absolute and Apparent Magnitude Scaling Design Mapping Requirements 173 Implications 141 Data Limitations 176 Range Grading 142 Communicating With Cartograms 176 Proportional Midpoint Range Grading 143 Recognizing Shapes 176 Proportional Symbol Legend Design 144 Estimating Areas 177 Graphic Design Considerations For Proportional A Communication Model 177 Point Symbol Maps 145 Advantages and Disadvantages 178 Graphic Treatment of Proportional Symbols 145 Design Strategies Recap—Legends, Inset Maps, and Overlapping Symbols 146 Labeling 179 Labeling Symbols 147 Bivariate Cartograms 180 ddeenn4433882233__ffmm__ii--xxvvii..iinndddd PPaaggee vviiiiii 77//1177//0088 88::3377::2299 PPMM uusseerr--ss117744 //VVoolluummeess//220022//MMHHDDQQ002222//mmhhddeenn66//ddeenn66ffmm viii CONTENTS Cartogram Construction 181 Historical Highlights of The Method 191 Manual Methods 181 Early Flow Maps 191 Automated Solutions 182 Flow Maps in Economic Geography 191 Designing Flow Maps 192 11 DYNAMIC REPRESENTATION: THE Map Organization and Figure-Ground 193 DESIGN OF FLOW MAPS 188 Projection Selection 193 Essential Design Strategies 194 The Purpose of Flow Mapping 188 Line Scaling and Symbolization 194 Quantitative Flow Maps 189 Treatment of Symbols 196 Data Suitability 189 Legend Design 196 Directed and Undirected Flows 189 Innovative Solutions 197 The Relevance of Flow Routes 190 Summary of Mapping Techniques 199 PART III DESIGNING THEMATIC MAPS 203 12 THE MAP DESIGN PROCESS AND Strong Edges and Figure Development 220 The Interposition Phenomenon 221 THE ELEMENTS OF MAP Figures and Grounds in the Map Frame 221 COMPOSITION 204 The Special Case of the Land-Water Contrast 222 The Design Process 204 Vignetting for Land-Water Differentiation 223 Design Evaluation 205 Designing the Page-Size Map 223 Creativity and Visualization 205 Graphic Ideation 206 13 MAKING THE MAP READABLE: Experimentation 206 THE INTELLIGENT USE OF Map Aesthetics 207 TYPE 226 The Map’s Design Elements 207 Design Levels on The Map 208 Functions of Map Lettering 226 Elements of Map Composition 209 The Elements of Type 227 Purpose of Map Composition 209 Typeface Characteristics 227 Planar Organization of the Visual Elements 209 Letterform Components 227 Balance 209 Typeface Style and Classifi cation 228 Focus of Attention 212 The Personality of Type 230 Internal Organization 212 The Legibility of Type 231 Contrast and Design 213 Cartographic Requirements 232 Line Contrast 213 Type Font and Type Families 232 Texture Contrast 214 Type Size 233 Value Contrast 214 Type Form 234 Variation of Detail 214 Type Width 234 Color Contrast 214 Type Weight 234 Vision Acuities 215 Type Color 234 Visual Acuity 215 Letter, Word, and Line Spacing 235 Resolution Acuity 215 Guidelines For Type Selection and Placement 236 The Visual Hierarchy of Map Organization: The Use of Capital and Lowercase Letters 237 Figure-Ground Relationship 215 The Placement of Lettering 237 Visual Hierarchy Defi ned 216 Point-Symbol Labeling 237 Customary Positions of Map Elements in the Hierarchy 216 Linear Feature Labeling 240 Achieving the Visual Hierarchy 217 Area Feature Labeling 241 Fundamental Perceptual Organization of the Two- Placement and Design of Titles and Legends 241 Dimensional Visual Field: Figure and Ground 217 Scales and North Arrows 243 Source and Author Information 243 Perceptual Grouping Principles 218 Figure Formation and Closure 219 Practical Example 244 ddeenn4433882233__ffmm__ii--xxvvii..iinndddd PPaaggee iixx 77//1177//0088 88::3377::2299 PPMM uusseerr--ss117744 //VVoolluummeess//220022//MMHHDDQQ002222//mmhhddeenn66//ddeenn66ffmm CONTENTS ix 14 PRINCIPLES FOR COLOR Device Limitations 256 Web Safe Colors 257 THEMATIC MAPS 246 Color Matching Systems 257 Light and the Color Spectrum 247 Color Interaction 257 Color Perception 248 Simultaneous Contrast 257 The Human Eye 248 Successive Contrast 257 Physical Properties of Color 248 Color Constancy 258 Color Theories 250 Subjective Reactions to Color 258 Additive Color Theory 250 Color Preferences 258 Subtractive Color Theory 250 Colors in Combination 258 The Desert Island Experiment 250 Connotative Meaning and Color 259 Advancing and Retreating Components of Color 251 Colors 259 Hue 251 Color in Cartographic Design 259 Saturation 252 The Functions of Color in Value 252 Design 259 Munsell Approach 252 Design Strategies for the Use Color Models 253 of Color 260 HSV 253 Developing Figure and Ground 260 HSB/HSL 254 The Use of Color Contrast 261 RGB 254 Developing Legibility 261 Cie Lab 254 Color Conventions in Mapping 261 CMYK 255 Color Harmony in Map Design 264 Grayscale 256 PART IV MAP PRODUCTION TECHNIQUES 267 15 PRINTING FUNDAMENTALS AND Step Three: Color Separation and Plate Generation 275 PREPRESS OPERATIONS FOR THE Step Four: Digital Color Proof 276 CARTOGRAPHER 268 Step Five: The Press Run 276 Step Six: Post-Press Operations 277 Cartography and Digital Printing 269 Digital Presses 278 Getting Started 269 Digital Printing Presses 278 Color Model 269 Digital Production Presses 278 Desktop Printing 269 Laser Printers 269 Inkjet Printers 270 16 INTRODUCTION TO VIRTUAL AND Plotters 270 Dye-Sublimation Printers 270 WEB MAPPING 280 Commercial Printing Technology 270 Virtual and Web Mapping Brief History of Commercial Printing 270 Introduction 280 Relief—Letterpress 270 Map Formats and Structures 282 Intaglio—Engraving 271 Raster Graphics 282 Planar—Lithography 271 Raster Concepts 283 Cartographic Design and the Printer 272 Selected Raster Image Formats 284 Commercial Printing 272 Animated Raster Map Formats 286 Prepress Map Editing 272 Vector Graphics 286 File Preparation 273 Vector Concepts 286 Service Bureau and Prepress Proofi ng 273 Selected Vector Formats 287 The Map Production Process 273 Understanding the Medium 287 Modern Offset Lithography 273 Key Internet Concepts 288 Step One: Design and Page Layout 274 The World Wide Web 288 Step Two: Printer’s Precheck 275 The Graphics Display Monitor 289