A to Z GIS (Esri) (Z-Library)

Esri Press, 380 New York Street, Redlands, California 92373-8100 Copyright © 2025 Esri All rights reserved. e-ISBN: 9781589488120 The Library of Congress has cataloged the print edition as follows: 2024948461 The information contained in this document is the exclusive property of Esri or its licensors. This work is protected under United States copyright law and other international copyright treaties and conventions. No part of this work may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying and recording, or by any information storage or retrieval system, except as expressly permitted in writing by Esri. All requests should be sent to Attention: Director, Contracts and Legal Department, Esri, 380 New York Street, Redlands, California 92373-8100, USA. The information contained in this document is subject to change without notice. US Government Restricted/Limited Rights: Any software, documentation, and/or data delivered hereunder is subject to the terms of the License Agreement. The commercial license rights in the License Agreement strictly govern Licensee’s use, reproduction, or disclosure of the software, data, and documentation. In no event shall the US Government acquire greater than RESTRICTED/LIMITED RIGHTS. At a minimum, use, duplication, or disclosure by the US Government is subject to restrictions as set forth in FAR §52.227-14 Alternates I, II, and III (DEC 2007); FAR §52.227-19(b) (DEC 2007) and/or FAR §12.211/12.212 (Commercial Technical Data/Computer Software); and DFARS §252.227- 7015 (DEC 2011) (Technical Data–Commercial Items) and/or DFARS §227.7202 (Commercial Computer Software and Commercial Computer Software Documentation), as applicable. Contractor/Manufacturer is Esri, 380 New York Street, Redlands, California 92373-8100, USA. Esri products or services referenced in this publication are trademarks, service marks, or registered marks of Esri in the United States, the European Community, or certain other jurisdictions. To learn more about Esri marks, go to: links.esri.com/EsriProductNamingGuide. Other companies and products or services mentioned herein may be trademarks, service marks, or registered marks of their respective mark owners. For purchasing and distribution options (both domestic and international), please visit esripress.esri.com. 189765

Preface The previous edition of this dictionary came out in 2006, nearly 20 years ago, and much has changed in that time. Geographic information systems (GIS) are now indispensable tools that have transcended their initial applications in government, utilities, and natural resource management. Today, GIS technology is used across diverse sectors such as urban planning, health care, transportation, and others. This broad adoption underscores the need for a clear and comprehensive understanding of the terminology associated with GIS. Because of its interdisciplinary nature, GIS has borrowed terms from related elds. In many cases, the meanings of these words have evolved and shifted over time. Over the last 20 years, numerous new terms have been added to the dictionary, and many existing terms have been rened or redened. With nearly 3,000 terms, A to Z GIS: An Illustrated Dictionary of Geographic Information Systems was designed to be a comprehensive technical dictionary for GIS students and professionals alike. Our goal for this dictionary was to create denitions that are technically accurate yet not intimidating to the GIS novice. Choosing terms The rst step in creating a dictionary is choosing which terms to include and which to leave out. This process was a challenge, since there are surprisingly few “pure” GIS terms. Most terms used in GIS have been adopted from such related elds as cartography, computing, geodesy, mathematics, remote sensing, statistics, and surveying. Our solution was to identify two classes of terms within the lexicon:

Core GIS terms that describe GIS concepts, processes, and operations. Although many of these terms may have origins in other elds, they are more strongly correlated with GIS than with any related eld. We included as many of these terms as possible. Terms from related elds such as cartography, computing, geodesy, geography, GPS, and remote sensing. These can be thought of as source elds that have lent methods, data, theory, and metaphors to GIS. We included the terms from related elds that GIS practitioners or students are mostly likely to come across in the course of their activities but left out terms that lie outside the GIS context. Writing the definitions GIS is an evolving science, and we work to remain aware of and dene terms based on current developments in numerous interconnected disciplines. In 2006, when this book was rst published, we chose the original list from a database of thousands of potential terms and denitions used in glossaries and dictionaries across Esri. Our nal list was carefully reviewed by subject matter experts and editors at Esri as well as an external panel of academic reviewers for consistency and accuracy, and their insights were invaluable. Since that time, the denitions we add continue to follow the growth of GIS and its partner elds, helping new generations of users improve their understanding. Creating the illustrations The dictionary’s illustrations were created by Kelly Brownlee, featuring some by Jennifer Jennings from the previous edition. Brownlee’s challenge was to reimagine Jennings’ illustrations and pair clarity and technical accuracy with extreme simplicity. For the maps in this dictionary, the goal of conveying the main idea of a concept in a tight space often meant a departure from traditional cartographic methods.

The future This dictionary has truly been a collaborative eort, and we are grateful to all the subject matter experts, reviewers, and other sta and contributors who have been involved in its compilation. The expertise that has gone into this dictionary is broad, but we welcome feedback and alternative interpretations. Those who wish to provide feedback may do so through the online GIS Dictionary at support.esri.com/gisdictionary or by email at gisdictionary@esri.com. We will consider all viewpoints and submissions for future printings and editions. GIS has a strong future, and as applications for GIS multiply, GIS terminology will continue to evolve and require denition.

Acknowledgments We extend our gratitude to Jack Dangermond, cofounder and president of Esri, for his support of this book, and for providing the kind of environment that fosters creativity and collaboration. More than 200 dedicated individuals at Esri have contributed denitions, edits, or comments for A to Z GIS. Without their collaboration and expertise, this book would not exist. We sincerely appreciate everyone who took time out of their busy schedules to write and review terms and denitions and answer our questions. Je Liedtke, John Nelson, Kevin M. Kelly, and Tim Ormsby in particular were instrumental. We are especially thankful to the dictionary editing team, Rebekah Folsom, Sarah David, Shanon Sims, and Molly Zurn, who maintain the dictionary online and helped us immensely with this new edition. Big thanks to the previous edition’s editors Tasha Wade and Shelly Sommer, without whom there would be no A to Z GIS. Lastly, this new edition shines with the wonderful new illustrations by Kelly Brownlee. Special thanks to Steve Frizzell, Craig Carpenter, and Victoria Roberts for their guidance in illustrating each term eectively. Contributors within Esri from 2005 to 2024 include Eric Akin, Rebeka Alvarez-Heck, Jamil Alvi, Christine Anthony, David Arctur, David Austin, Jonathan Bailey, Scott Ball, Peter Becker, Cody Benkelman, Mrinmayee Bharadwaj, Victor Bhattacharyya, Suzanne Boden, Bob Booth, Hal Bowman, Judy Boyd, Dave Boyles, Steve Bratt, Joe Breman, Patrick Brennan, Pat Breslin, Evan Brinton, Lee Brinton, Clint Brown, Aileen Buckley, Rob Burke, Kathy Capelli-Breier, Krista Carlson, Tarun Chandrasekhar, Colin Childs, Dan Clark, Kristin Clark, Shane Clarke, Dan Cobb, Amy Collins, Clayton Crawford, David Crawford, Scott Crosier, Brian Cross, Matt Crowder, Katy Dalton, Dave Danko, Jane Darbyshire, Marilyn Daum, Eleanor Davies, David

Davis, Nana Y. Dei, Jon DeRose, Mara Dolan, Thomas Dunn, Sara Eddy, Cory Eicher, Gregory Emmanuel, Rupert Essinger, Mark Feduska, Katherine Fitzgerald, Derek Foll, John Foster, Witold Fraczek, Steve Frizzell, Charlie Frye, Ignacia Galvan, Peng Gao, Phoebe Gelbard, Sophia Giebler, Shelly Gill, Craig Gillgrass, Rhonda Glennon, Lisa Godin, Craig Greene, Craig Greenwald, Lauren Scott Grin, Michael Grossman, Sarah Hanson, Paul Hardy, Melanie Harlow, Alan Hatakeyama, Mark Henry, Jim Herries, Catherine Hill, Vicki Hill, Tim Hodson, Jennifer Itatani, Jen Jennings, Robert Jensen, Ann Johnson, Karen Johnston, Kevin Johnston, Catherine Jones, Rob Jordan, Gary Kabot, Peter Kasianchuk, Amy Kastrinos, Tim Kearns, Anita Kemp, Melita Kennedy, Jon Kimerling, Steve Kopp, Kory Kramer, Konstantin Krivoruchko, Al Laframboise, Juan Laguna, Derek Law, Christine Leslie, Will Lewis, Shing Lin, Adrien Litton, Mike Livingston, Robin Lovell, Clint Loveman, Steve Lynch, Kevin M. Kelly, Andy MacDonald, Gary MacDougall, Alan MacEachren, Keith Mann, Michael Mannion, Frank Martin, Jim Mason, Sean McCarron, Jill McCoy, Heather McCracken, Matt McGrath, Ginger McKay, Elizabeth Mezenes, Christopher Moore, Scott Morehouse, Bill Moreland, Doug Morgenthaler, Joel Morrison, Makram Murad, Diana Muresan, Jonathan Murphy, Scott Murray, Claudia Naber, Brad Niemand, Nawajish Noman, Serene Ong, Sarah Osborne, Krista Page, Brian Parr, Jamie Parrish, Christopher Patterson, Meredith Payne, Andrew Perencsik, Kim Peter, Rhonda Pfa, Morakot Pilouk, Christie Pleiss, Ghislain Prince, Edie Punt, Sterling Quinn, Amir Razavi, Je Reinhart, Je Rogers, Rick Rossi, Sara Sanchez, Bojan Šavrič, Sandi Schaeer, Frederic Schettini, Charles Serafy, Je Shaner, Nathan Shephard, Gillian Silvertand, Shanon Sims, Daryl Smith, Damian Spangrud, Cathy Spisszak, Marc St. Onge, Bjorn Svensson, Je Swain, Sally Swenson, Agatha Tang, Corey Tucker, Patty Turner, Sarah VanHoy, Marika Vertzonis, Aleta Vienneau, Nathan Warmerdam, David Watkins, Kyle Watson, Lindsay Weitz, Tiany Wilkerson, Craig Williams, Jason Willison, Jill Williston, Niki Wong, Simon

Woo, Randy Worch, Dawn Wright, David Wynne, Lingtao Xie, Hong Xu, Rebecca Yarbrough, and Larry Young. We are also indebted to the Esri Copyediting team and the following academic and industry reviewers and contributors: Dr. Barbara Butteneld, Department of Geography, University of Colorado, Boulder; Jerey Danielson, U.S. Geological Survey; Dr. Michael N. DeMers, Department of Geography, New Mexico State University; Mr. Jerey D. Hammerlinck, University of Wyoming, Laramie; Dr. Duane F. Marble, The Ohio State University; Professor W. Andrew Marcus, University of Oregon; Dr. Nicholas Nagle, Department of Geography, University of Colorado, Boulder; and Roland Viger, U.S. Geological Survey. Image and data credits igital orthophoto quadrangle: Image from U.S. Geological Survey. raping: Cartography by Craig Carpenter, Esri; image from U.S. Geological Survey. illshading: Cartography by Daniel Coe, Washington Geological Survey. andsat: Image from U.S. Geological Survey. Quadrangle: Image from U.S. Geological Survey. Voxel: Cartography by Nathan Shephard, Esri; data courtesy of the World Ocean Database (WOD), from NOAA.

How to use this dictionary Parts of an entry Headword—The term being dened is in bold type at the beginning of the entry. Taxonomy—This is used to classify denitions by subject area and is set in brackets. Denition—The meaning of the headword is explained in the denition. For terms that have more than one denition, the denitions are numbered and placed in order. GIS-relevant denitions typically appear rst; denitions from related elds follow. Cross-references—Listed after the last denition in an entry with “See also,” these terms are related in some way to the headword. They might be synonyms, antonyms, broader terms, or narrower terms. Illustration—Illustrations appear after the denition they refer to and are labeled with the headword.

# 1NF See rst normal form. 24-bit color [VISUALIZATION] An 8-bit byte used for the red, green, and blue (RGB) components of a pixel color. Also called true color. See also pixel, RGB. 2NF See second normal form. 3D feature [3D GIS] A representation of a three-dimensional, real-world object in a map or scene, with elevation values (z-values) stored within the feature’s geometry and optionally, attributes stored in a feature table. In applications such as CAD, 3D features are often referred to as 3D models. See also 3D model, elevation, feature, real world, z-value. 3D graphic [3D GIS] A representation of a three-dimensional, real-world object in a map or scene, with elevation values (z-values) stored within the feature’s geometry. Unlike 3D features, 3D graphics do not have attributes. See also 3D model, graphic, real world, z-value. 3D mesh [3D ANALYSIS] A digital 3D textured model where the ground and aboveground feature surfaces are densely and accurately reconstructed. See also edge, face, surface. 3D model [3D GIS] A construct used to portray an object in three dimensions. In GIS, 3D models are often referred to as 3D features. 3D multipatch See multipatch.

3D object [3D ANALYSIS] A digital representation of a real-world feature with three-dimensional geometric characteristics, such as length, width, and height. Within GIS, 3D objects are used for spatial modeling and analysis. See also geometry, real world. 3D polygon See polyhedron. 3D scene [3D ANALYSIS, ESRI SOFTWARE] A method used to display three- dimensional data. The viewer can adjust the display of 3D data to identify and select features. See also scene. 3D shape [3D GIS] A point, line, or polygon that stores x-, y-, and z- coordinates as part of its geometry. A point has one set of z-coordinates; lines and polygons have z-coordinates for each vertex in a shape. See also polyhedron, sphere, spheroid. 3D surface area [CARTOGRAPHY] An area calculation that takes the slope of the landscape into account. See also slope. 3D symbol [SYMBOLOGY] A symbol with properties that allow it to be rendered in three dimensions. See also symbol. 3D tile [3D ANALYSIS] A data format used to stream and visualize large-scale 3D geospatial datasets. 3D tiles are specically designed for displaying complex 3D models, terrain, and other spatial data with smooth rendering and interaction. See also 3D model, smoothing, terrain surface. 3D-perspective surface map [MAP DESIGN] A map that shows a continuous surface in oblique perspective. See also continuous surface, oblique-perspective map. 3NF See third normal form.

A abscissa [COORDINATE SYSTEMS] In a rectangular coordinate system, the distance of the x-coordinate along a horizontal axis from the vertical or y-axis. For example, a point with the coordinates (7,3) has an abscissa of 7. See also ordinate. abscissa absolute accuracy [COORDINATE SYSTEMS, DATA QUALITY] The degree to which the position of an object on a map conforms to its correct location on the earth according to an accepted coordinate system. See also coordinate system, relative accuracy. absolute coordinates [COORDINATE SYSTEMS] Coordinates that are referenced to the origin of a given coordinate system. See also coordinates.

absolute relief [CARTOGRAPHY] The elevation values at locations in the landscape given in reference to a specied datum. See also datum, elevation. absolute relief mapping method [CARTOGRAPHY] A mapping method for showing numeric elevation information. acetate [ESRI SOFTWARE] Circles, lines, polygons, points, or markers that become transparent when not active. Acetate features are overlaid on other map layers and can be independently annotated. across-track scanner [REMOTE SENSING] Also known as a whisk broom sensor. A remote-sensing tool with an oscillating mirror that moves back and forth across a satellite’s direction of travel, creating scan line strips that are contiguous or that overlap slightly to produce an image. See also along-track scanner, sensor. across-track scanner

active remote sensing [REMOTE SENSING] A remote sensing system, such as radar, that produces electromagnetic radiation and measures its reection back from a surface. See also passive remote sensing, remote sensing. actual scale [CARTOGRAPHY] The local measurement of scale at any point on a map; actual scale can vary from one location on a map to another. See also principal scale, scale factor. acutance [PHOTOGRAMMETRY] A measure, using a microdensitometer or other instrument, of how well a photographic system shows sharp edges between contiguous bright and dark areas. See also remote sensing, microdensitometer, contiguous. address [CADASTRAL AND LAND RECORDS] The designation of a location, typically used for navigation or postal service purposes, which consists of text and numeric elements, such as a street number, street name, city, and postal code arranged in a specic format. See also geocoding, location, matching. address data [GEOCODING] Data that contains address information used for geocoding. Address data may consist of one individual address or a table containing many addresses. See also geocoding. address data format [GEOCODING] The arrangement of address information in a database, most often consisting of such address elements as house number, street direction, street name, street type, city, and postal code. See also geocoding. address data model [GEOCODING] The rules of a geodatabase that specically accommodate address-related material, such as streets, zones, and ranges. Relevant properties include the allowed address elements, their attribute values, and the relationships between these. An address data model also facilitates address data storage. See also geocoding.

address element [GEOCODING] One of the components that compose an address. House numbers, street names, street types, and street directions are examples of address elements. See also address, address data, locator, geocoding. address event [ADDRESS MATCHING, ESRI SOFTWARE] Features that can be located based on address matching with a street network or other address identier, such as postal codes or lot numbers. See also address matching, event, postal code. address event table [GEOCODING, ESRI SOFTWARE] A document object containing addresses but no spatial reference information. Using GIS software, address event tables can be geocoded to create a spatial data layer. See also address, address event, geocoding, table. address field [GEOCODING, ESRI SOFTWARE] A column in a table that stores one or more address elements. An address eld can be present in reference data, address data, or both. See also eld, geocoding. address format [GEOCODING] The particular structure and arrangement of address elements and a corresponding method of matching that can be used for a specic application. The address format may vary based on locale or country. See also geocoding, locale. address geocoding See geocoding. address locator See locator. address locator property See locator property. address locator style See locator style.

address matching [ADDRESS MATCHING, ESRI SOFTWARE] A process that compares an address or a table of addresses to the address attributes of a reference dataset to determine whether a particular address falls within an address range associated with a feature in the reference dataset. If an address falls within a feature’s address range, it is considered a match and a location can be returned. See also geocoding, matching, match score. address range [GEOCODING, ESRI SOFTWARE] Street numbers running from lowest to highest along a street or street segment. Address ranges often indicate ranges on the left and right sides of streets. See also address, geocoding. address standardization [GEOCODING] The process of breaking down an address into elements and converting those elements with standard abbreviations or spellings. For best practices, this process applies to preparing the reference data and address data for matching. See also address, geocoding. adjacency 1. [GEOGRAPHY] A type of spatial relationship in which two or more polygons share a side or boundary.

adjacency 1 2. [EUCLIDEAN GEOMETRY] The state or quality of lying close or contiguous. See also boundary, conterminous, contiguous. adjacency query [SPATIAL ANALYSIS] A statement or logical expression used to select geographic features that share a boundary. See also adjacency. Advanced Very High Resolution Radiometer [REMOTE SENSING] Also known by the acronym AVHRR. A sensor on National Oceanic and Atmospheric Administration (NOAA) polar-orbiting satellites for measuring visible, shortwave, mediumwave, and longwave (thermal) radiation reected or emitted from vegetation, cloud cover, shorelines, water, snow, and ice. AVHRR data is often used for weather prediction, sea surface, and vegetation mapping. The highest AVHRR resolution is 1.1 km per pixel at nadir; the swath is 2399.5 km. See also electromagnetic radiation, remote sensing, sensor.

aerial [PHYSICS] Refers to the air or atmosphere. See also aerial photograph, areal. aerial photograph [AERIAL PHOTOGRAPHY] A photograph of the earth’s surface taken from an aircraft, satellite, or other remote platform. Aerial photography is often used as a cartographic data source for basemaps, to locate geographic features, and to interpret environmental conditions. See also orthophoto, oblique photograph, vertical photograph. aeronautical chart [CARTOGRAPHY] A map created specically for air navigation. See also chart, marine navigation, navigation chart, sectional aeronautical chart. affine transformation 1. [COORDINATE SYSTEMS, SPATIAL ANALYSIS] A geometric transformation that scales, rotates, skews, or translates images or coordinates between any two Euclidean spaces. It is commonly used in GIS to transform maps between coordinate systems. Ane transformations preserve parallel lines, ratios of distances between points, and all points on a straight line remain on a straight line; ane transformations do not necessarily preserve angles or lengths.