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GIS Data Conversion: Strategies, Techniques, and Management
Author: Hohl, Pat
Cover: cover
Pages: 423
List Price: $52.95
Published by Onword Press
Date Published: 11/1997
ISBN: 1566901758
 Table of Contents
SECTION 1: Introduction 1
Introduction and Overview 3
Ensuring Successful Conversion 3
Book Audience 4
Who, What, Why, Where, and When? 5
Different Perspectives 6
Book Organization 7
Introduction and Overview 7
Project Management 7
GIS Data Sources 9
Data Conversion/Input Methodologies 9
Quality Control/Quality Assurance 10
Summary 10
Chapter 2: Data, the Foundation of GIS 11
Data Definitions 11
Information versus Data 11
Precision versus Accuracy 13
Data Types 14
Spatial Data 15
Attribute Data 17
Temporal Data 17
Metadata 17
Data Sources 17
Measured Data 18
Inferred Data 18
Imported (and Converted) Data 18
Data Processing 18
Acquisition 19
Retrieval 19
Analysis 19
Presentation 19
Converting, Exporting, and Importing 20
Relational Data Model 20
Entities 20
Relationships 21
Normalization 21
Conclusion 25
References 26
SECTION 2: Project Management 27
Chapter 3: Conversion Resources and 29
Structures
Staffing Needs 29
Data Conversion Expert 31
Computer Expert 32
Cartographic and Geographic Expert 33
Consultant and Conversion Vendor 33
Administrative Support Personnel 34
Digitizer 34
Hardware and Software 35
Determining Appropriate Equipment 35
Plotters 35
Data Manipulation Requirements 36
Budget 36
Up-front Funding 37
Budget Flexibility 37
Conversion Structures 38
Departments 38
Multi-participant GIS 39
Data Sharing Guidelines 44
Where to Look 45
Benefits and Challenges of Data Sharing 46
Conversion Pilot 50
Limiting the Sample Area 50
Limiting Risk 51
Evaluating the Pilot 52
Conversion Philosophies 53
Incremental Conversion 53
Blitzkrieg Conversion 57
References 60
Acknowledgments 61
Chapter 4: Project Planning and Management 63
Project Elements 64
Planning 66
Obtain Input and Support from Executives 66
Perform Needs Assessments of End Users 68
Establish Goals, Objectives, and 69
Strategies
Test Project Feasibility 71
Prioritize 73
Prepare a Budget 74
Prepare a Time Line 74
Articulating the Plan 74
Gathering Resources 75
Working Toward Milestones 75
Demonstrating Usability 76
Long-term Data Maintenance 79
Strategic Issues 80
Consultant versus In House 80
Choosing a Consultant 82
Traditional Procurement 84
New Procurement Options 88
Key Risk Areas 91
Change Control 91
Guarding Against "Foolproof" Claims 92
Database Design Parameters 92
Data Quality 93
Cost and Schedule 94
Communication 94
User Acceptance 95
Data Maintenance 96
Management Support 96
Procedural Innovation 97
Mitigating Risk and Liability 97
Conclusion 98
Acknowledgments 98
Chapter 5: Documenting a Data Conversion 99
Effort
Benefits of Documentation 100
Creating Data Conversion Documentation 101
Keep It Simple 101
Make It Portable 101
Address Motivation 102
Provide as Much Detail as Possible, and 103
Then Some
What to Include 103
Project Implementation Objectives and 103
Priorities
Database Design 104
Data Conversion Plan and Procedures 107
Quality Control Plan and Procedures 108
Post-conversion Updates 110
New Stuff "Outside the Box" 111
A Final Thought about Documentation 111
Acknowledgments 112
SECTION 3: Understanding the Target System 113
Chapter 6: Understanding the Target System 115
Different Levels of GIS Use 115
Computer Networks 116
Network Operating Systems 118
Lantastic 118
UNIX 118
Novell 118
Windows NT 119
The Internet 119
Network Security 120
Computer Operating Systems 121
UNIX 121
Disk Operating System (DOS) 121
Windows 122
Windows 95 122
Windows NT 123
Macintosh OS 123
Mainframes 124
Web Browsers 124
Computer Hardware 126
Processors 126
Storage Devices 127
Input Devices 129
Output Devices 131
Network Connectivity Devices 132
GIS Software 132
Non-commercial GIS Software 132
Commercial GIS Software 132
Database Design 135
Design Elements 136
Design Stages 137
Design Drivers 137
Summary 138
Acknowledgments 138
SECTION 4: GIS Data Sources 139
Chapter 7: Data Source Types and Preparation 141
Data Source Types 141
Existing Digital Sources 142
Existing Vector Data Sources 142
Existing Tabular Data Sources 144
Existing Raster Data Sources 145
Existing Hardcopy Data Sources 145
GIS Data Synthesis 151
Aerial Photography and Planimetric Data 151
Compilation
Digital Orthophotography 152
Field Capture of Data 153
COGO Input 153
Optimal Data Source Selection 154
Feature Quantities 155
Data Source Preparation for Entry into the 156
GIS
Retrieval/Duplication of Data Sources 156
Freezing Source Updates 157
Scrubbing Data Sources 157
Posting of Backlog 157
Cross-References, Conflict Resolution, 158
and Cleansing Records
Source Document Inventory, Control, and 158
Tracking
Acknowledgments 159
Chapter 8: Data Models, Collection 161
Considerations, and Cartographic Issues
Raster versus Vector Data Representation 161
Issues
Characteristics of Geographic Phenomena 162
Locational Precision 163
Speed of Analytical Processing and 164
Computing
Data Storage 164
Data Issues 167
Data Collection in GIS 167
Primary Data Collection 167
Secondary Data Collection 170
Cartographic Data Issues 172
Geographic Information Content 172
Map Scale and Generalization 173
Graphic Representation of Spatial Features 176
Summary 178
Acknowledgments 178
Chapter 9: External Data Sources and Formats 179
Considerations When Using External Data 179
Examples of External GIS Data 184
Base Map Data 184
Thematic Data Sets 190
Elevation Data 192
Sources of External Data 194
Other Sources of Information 202
Acknowledgments 203
SECTION 5: Data Conversion/Input Methodologies 205
Chapter 10: Airborne Sensing Systems and 207
Techniques
Data Types 207
Types of Photogrammetry 211
Map/Photo Scale 212
Resolution 214
Camera Technology 215
Digital Frame Cameras 216
Aerial Photography 217
Flight Conditions 222
Photo Control 224
Traditional Field Surveys 224
GPS Field Surveys and Aerotriangulation 225
Chapter 11: Producing GIS Data from Aerial 229
Photos
Stereomapping 229
Planimetric Detail 233
Softcopy Mapping 234
Image Analysis 237
Digital Orthophotography 238
Orthographic Projections 239
Digital Orthophoto Process 239
Orthophotos as Base Maps 243
3D Images 244
Design Issues 244
Project Planning Considerations 245
Chapter 12: Global Positioning Systems 251
Comparing GPS Data Acquisition to Other 253
Methods
GPS Method of GIS Data Collection and 254
Conversion
What Can Go Wrong? 255
Differential Correction 255
Data Conversion to GIS 256
Other Applications 257
GPS Advantages and Disadvantages 257
Advantages 257
Disadvantages 258
The Future 258
Chapter 13: Scanning 259
Why GIS Data Are Different 259
Advantages of Vector Data 262
How Scanning Works 263
About Scanners 264
Image Quality 266
Digital versus Visual Output 266
Thresholding 267
Brightness and Contrast 268
Gamma Correction and Thresholding 271
Dynamic Thresholding 271
Throughput 272
Optimal Environment 273
Memory Guidelines 273
Resolution 274
Scan Heads 274
Optical versus Interpolated Resolution 275
Scale and Accuracy in Relation to 280
Resolution
Scanning Accuracy 281
What Accuracy Is Required? 281
Accuracy and Source Documents 282
Scanner Accuracy 283
Map Preparation for Scanning 285
Vectorization 287
Intersections 290
Generalization 290
Intersections versus Generalization 291
Attributes 292
Vectorization Tricks of the Trade 292
Color Scanning 293
Color Scanner 294
Optical Character Recognition 296
Good News About OCR 296
Bad News About OCR 297
Data Storage 298
Making the Most of What You Have 299
Data Delivery 300
Summary 301
Acknowledgments 301
Chapter 14: Keyboard Entry of Attribute Data 303
Single Key Data Entry 305
Data Preparation Requirements 306
Hardware/Software Requirements 307
Data Validation Considerations 307
Data Quality Control 308
Double Key Data Entry 310
Data Preparation Requirements 311
Hardware/Software Requirements 315
Chapter 15: Spatial Data Transfer Standards 319
General Characteristics 320
No Information Loss 320
Self-contained Transfers 321
Not Intended for Processing 322
Non-proprietary Format 323
Three Model Levels 323
Wide Spectrum of Spatial Data Models 325
Supported
Feature Catalog 325
Files of the Transfer 326
Impact on the Data Consumer 327
Barriers to Spatial Data Exchange 327
Target System Must Support Data Set 328
Learning the Standard 329
Spatial Object Terms 331
Data Quality Report 332
Attributes 334
GIS Import Process 336
Automatic Conversion/Direct Import 336
Advanced Import Options 338
Format Converter Utilities 339
Viewing Utilities 340
An SDTS Import Example Using ARC/INFO 342
Troubleshooting 349
Diagnosing the Problem 349
Common Problems 349
Where to Find Help 352
Suggested Places for Help 352
Acknowledgments 353
References 353
SECTION 6: Quality Control/Quality Assurance 355
Chapter 16: Quality Control/Quality Assurance 357
Attribute versus Graphic Quality 358
Attribute Accuracy 358
What About the Data Source? 359
Spatial Accuracy 360
Quality Control versus Quality Assurance 362
Quality Control Definition and Philosophy 362
Data Acceptance Criteria 368
Define Criteria for Measuring Quality 369
Establish Procedures for Quality 372
What Types of Checks When? 372
Define Detailed Quality Control/Quality 374
Assurance Procedures
Documentation of Quality 374
Quality Control/Quality Assurance Log 375
Forms
Automated Reports and Logs 375
Problem Resolution 376
Managing Quality Risks 379
Documentation of Quality Requirements 379
Set Your Sights 380
Providing Adequate Resources 380
Resolve the Quality versus 381
Schedule/Budget Conflict
Appendix A: Glossary 383
Appendix B: Contributors 393
Index 397
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