# Lining Up Data in ArcGIS: A Guide to Map Projections

"Lining Up Data in ArcGIS: A Guide to Map Projections is an easy-to-navigate troubleshooting reference for any GIS user with the common problem of data misalignment. There are numerous scholarly volumes that delve into the mathematics of map projections, exhaustively detailing the calculations used to project data from the curved surface of the earth onto a

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## Overview

"Lining Up Data in ArcGIS: A Guide to Map Projections is an easy-to-navigate troubleshooting reference for any GIS user with the common problem of data misalignment. There are numerous scholarly volumes that delve into the mathematics of map projections, exhaustively detailing the calculations used to project data from the curved surface of the earth onto a flat piece of paper." Complete with full-color maps and diagrams, Lining Up Data in ArcGIS presents practical techniques on how to identify data projections, create custom projections to align data, and solve common data alignment problems. This book will benefit new and experienced GIS users alike.

## Product Details

ISBN-13:
9781589482494
Publisher:
ESRI Press
Publication date:
06/15/2010
Edition description:
New Edition
Pages:
200
Product dimensions:
7.90(w) x 9.90(h) x 0.60(d)
Age Range:
15 Years

## Related Subjects

Preface

Introduction

Chapter 1 Identifying the type of coordinate system for data using ArcMap 1

Features in vector datasets 2

Identifying the type of coordinate system for data using ArcMap 3

Examining the extent of the data 6

Summary 12

Chapter 2 Identifying the correct geographic coordinate system 13

Example of datum offset between NAD 1927 and NAD 1983 datums in a geographic coordinate system (GCS) 14

Example in which data with the unknown coordinate system is in a GCS, and reference data is in a projected coordinate system 21

Other issues to consider 24

Summary 26

Chapter 3 Identifying the projected coordinate system 27

State plane coordinate system 28

Universal transverse Mercator (UTM) coordinate system 32

Testing to identify the projected coordinate system for data 35

If state plane options do not align the data, testing for UTM 38

Other projected coordinate system options 40

Summary 41

Chapter 4 When standard coordinate systems don't work-working with nonstandard units 43

Customizing the UTM coordinate system with units of feet 44

Customizing the state plane coordinate system with units of inches 49

Units of international feet vs. U.S. survey feet 58

Saving the custom projection file to disk for future use 59

Defining the projection using the custom projection file 60

Summary 61

Chapter 5 Aligning CAD data---modifying a standard coordinate system 63

Issues to consider when working with CAD files in ArcMap 64

Procedures to address these issues 66

1 Identifying units of measure 66

2 CAD files created with references attached 69

3 If CAD data is in nonrotated local coordinates 69

5 Improving layer/level visibility 74

6 If CAD files were created in ground coordinates 74

Saving the custom projection file to disk 78

Applying the custom coordinate system to the CAD file 78

Summary 78

Chapter 6 Aligning rotated CAD data 79

Adjusting for the azimuth or rotation parameters 80

Other custom coordinate system options 94

Summary 95

Chapter 7 Why we need geographic (datum) transformations 97

What are geographic transformations? 98

Geographic transformation methods 100

Creating and saving a custom geographic transformation in ArcToolbox 106

Summary 108

Chapter 8 Applying geographic transformations 109

Applying geographic transformations in the ArcMap data frame 110

Changing the coordinate system of the ArcMap data frame 117

Applying geographic transformations in the Project tool in ArcToolbox 118

Summary 121

Chapter 9 "What map projection should I use for my project?" 123

Geographic coordinate systems 124

Projected coordinate systems 128

Deciding on the projection to use for your project 132

Creating the custom projection file in ArcMap 135

Summary 140

Chapter 10 Projection files and parameters; adding x,y data; the shape of buffers 141

Projection files installed with ArcGIS Desktop 142

Coordinate system parameters 142

What is a geographic coordinate system? 143

What is a projected coordinate system? 146

What is a local coordinate system? 148

Adding x,y data to ArcMap and converting to features in a shapefile or feature class 148

Why buffers displayed in ArcMap are not round 154

Summary 163

Appendix A 165

Appendix B 167

Appendix C 169

Data source credits 171

Index 173