GIS Dictionary

[business] A project management graph that displays tasks on a schedule, often used to plan and track projects. The Gantt chart was developed by the American mechanical engineer and management … Read more

A projected coordinate system that uses the transverse Mercator projection to divide the world into standard zones 6 degrees wide. Used mainly in Europe and Asia, the Gauss-Krⁿger coordinate system … Read more

A list of geographic place-names and their coordinates. Entries may include other information as well, such as area, population, or cultural statistics. Atlases often include gazetteers, which are used as … Read more

Acronym for Geographic Base Files/Dual Independent Map Encoding. Vector geographic base files made for the 1970 and 1980 U.S. censuses, containing address ranges, ZIP Codes, and the coordinates of street … Read more

[non-ESRI software] Acronym for Graphical Device Interface. A standard for displaying and transmitting text and graphical objects output devices, such as monitors and printers. GDI generally refers to the Windows … Read more

1 [map design] The abstraction, reduction, and simplification of features for change of scale or resolution. 2 [data editing] The process of reducing the number of points in a line … Read more

[computing] A search algorithm inspired by genetics and Darwin’s theory of natural selection. The algorithm goes through an iterative process of applying genetic operators, such as reproduction, mutation, and crossover, … Read more

1 [geodesy] Measured from the earth or the earth’s center. 2 [astronomy] Having the earth as a center.

[coordinate systems] A three-dimensional, earth-centered reference system in which locations are identified by their x-, y-, and z-values. The x-axis is in the equatorial plane and intersects the prime meridian … Read more

A horizontal geodetic datum based on an ellipsoid that has its origin at the earth’s center of mass. Examples are the World Geodetic System of 1984, the North American Datum … Read more

[coordinate systems] The angle between the equatorial plane and a line from a point on the surface to the center of the sphere or spheroid. On a sphere, all lines … Read more

[coordinate systems] The angle between the prime meridian and a line drawn from a point on the surface to the center of a sphere or spheroid. For an ellipsoid of … Read more

1 [geocoding] To assign a street address to a location. 2 [government] A code representing the location of an object, such as an address, a census tract, a postal code, … Read more

[geocoding] A feature class created by batch geocoding.

[ESRI software] An ArcGIS Server software component that provides programmatic access to an address locator and performs single and batch address matching. It is designed for use in building Web … Read more

[geocoding] A GIS operation for converting street addresses into spatial data that can be displayed as features on a map, usually by referencing address information from a street segment data … Read more

[ESRI software] An entity in the geocoding framework that drives the geocoding process.

[ESRI software] An index on reference data used by an address locator to search for matching records in the reference data. A geocoding index is either a file or a … Read more

[ESRI software] A conceptual entity of the geocoding framework that combines the interaction of the ArcGIS interface with the input parameters set in the address locator and the processes of … Read more

[geocoding] The steps involved in translating an address entry, searching for the address in the reference data embedded in an address locator, and delivering the best candidate or candidates. These … Read more

[ESRI software] Data that a geocoding service uses to determine the geometric representations for locations.

[programming] A collection of files that directs the geocoding engine in how to standardize address data and match it to the related location in the reference data. Each address locator … Read more

[ESRI software] In ArcGIS 8.3 and previous versions, an object that defines the process for translating nonspatial descriptions of places, such as street addresses, into spatial data that can be … Read more

[ESRI software] A template on which a geocoding service is built. Each template is designed to accommodate a specific format of address and reference data, and geocoding parameters. Geocoding style … Read more

[computing] The application of computer technology to spatial problems, including problems of collecting, storing, visualizing, and analyzing spatial data, and of modeling spatial system dynamics.

[ESRI software] A database or file structure used primarily to store, query, and manipulate spatial data. Geodatabases store geometry, a spatial reference system, attributes, and behavioral rules for data. Various … Read more

[ESRI software] The schema for the various geographic datasets and tables in an instance of a geodatabase. The schema defines the GIS objects, rules, and relationships used to add GIS … Read more

[ESRI software] In a geodatabase, a collection of feature classes stored together so they can participate in topological relationships with one another. All the feature classes in a feature dataset … Read more

[ESRI software] In ArcGIS, a method of distributing data across two or more geodatabases in order to synchronize data changes. An entire geodatabase or a subset of a geodatabase can … Read more

[ESRI software] A table in an ArcSDE geodatabase that stores geometric shapes for each feature. Feature tables are used in geodatabases that store data as a binary data type, such … Read more

[ESRI software] In ArcGIS, a coarse-grained object that represents a geodatabase. It allows software users to perform replication operations, data extraction and database query operations on a geodatabase over the … Read more

[ESRI software] Any organized collection of data in a geodatabase with a common theme.

The shortest distance between two points on the surface of a spheroid. Any two points along a meridian form a geodesic.

[geodesy] The science of measuring and representing the shape and size of the earth, and the study of its gravitational and magnetic fields.

A datum that is the basis for calculating positions on the earth’s surface or heights above or below the earth’s surface.

[coordinate systems] The angle that a line drawn perpendicular to the surface through a point on a spheroid makes with the equatorial plane.

[coordinate systems] The angle between the plane of the meridian that passes through a point on the surface of the spheroid and the plane of a prime meridian, usually the … Read more

A survey that takes the shape and size of the earth into account, used to precisely locate horizontal and vertical positions suitable for controlling other surveys.

[empty] The process of adding demographic and lifestyle data to your maps.

[map display] A designated boundary around a geometry that, if crossed, initiates a notification. Geofences are often used in real-time route Web applications.

[geography] Of or relating to the earth.

A reference system that uses latitude and longitude to define the locations of points on the surface of a sphere or spheroid. A geographic coordinate system definition includes a datum, … Read more

A measurement of a location on the earth’s surface expressed in degrees of latitude and longitude.

Information describing the location and attributes of things, including their shapes and representation. Geographic data is the composite of spatial data and attribute data.

[graphics map display] A graphic representation of a location; for example, a point to represent the location of a smokestack, or a polygon to represent the location of a toxic … Read more

[coordinate systems] A systematic conversion of the latitude-longitude values for a set of points from one geographic coordinate system to equivalent values in another geographic coordinate system. Depending on the … Read more

1 [geography] The study of the earth’s surface, encompassing the description and distribution of the various physical, biological, economic, and cultural features found on the earth and the interaction between … Read more

[government] A division of statistical geographic data, such as country, province, postal code, tract, or block group.

[geodesy] A hypothetical surface representing the form the earth’s oceans would take if there were no land and the water were free to respond to the earth’s gravitational and centrifugal … Read more

[geodesy] The height of the geoid above the ellipsoid.

[geodesy] The distance from the surface of an ellipsoid to the surface of the geoid, measured along a line perpendicular to the ellipsoid. The separation is positive if the geoid … Read more

[geolocating] The process of creating geographic features from tabular data by matching the tabular data to a spatial location. An example of geolocation is creating point features from a table … Read more

[ESRI software] The distance within which features in a geometric network are deemed to be coincident and, therefore, connected.

[remote sensing] The correction of errors in remotely sensed data, such as those caused by satellites or aircraft not staying at a constant altitude or by sensors deviating from the … Read more

[ESRI software] In ArcGIS, a dynamic process that can be applied within a representation rule to dynamically alter the geometry of features before they are drawn. Geometric effects can act … Read more

[Euclidean geometry] One of the most basic parts or components of a geometric figure: that is, a surface, shape, point, line, angle, or solid.

[ESRI software] Edge and junction features that represent a linear network, such as a utility or hydrologic system, in which the connectivity of features is based on their geometric coincidence. … Read more

[coordinate systems] The process of rectifying a raster dataset to map coordinates or converting a raster dataset from one coordinate system to another.

1 [Euclidean geometry] The measures and properties of points, lines, and surfaces. In a GIS, geometry is used to represent the spatial component of geographic features. 2 [mathematics] The branch … Read more

[programming] An OpenLS platform for wireless Web services defined by the Open Geospatial Consortium.

The study of the nature and origin of landforms, including relationships to underlying structures and processes of formation.

[analysisgeoprocessing] A GIS operation used to manipulate GIS data. A typical geoprocessing operation takes an input dataset, performs an operation on that dataset, and returns the result of the operation … Read more

[ESRI software] A computer in a network that is used to handle geoprocessing tasks. Geoprocessing servers may use UNIX or Windows platforms, and include a utility to schedule remote processing.

[ESRI software] Any settings that affect working with or running tools. Geoprocessing settings include the state of the ArcToolbox window, the state of the Environment Settings dialog box, and variables … Read more

[ESRI software] An ArcGIS tool that can create or modify spatial data, including analysis functions (overlay, buffer, slope), data management functions (add field, copy, rename), or data conversion functions.

[ESRI software] An ArcView Geocoding Windows dynamic link library (DLL) for use on ArcView 3.x. It exposes additional geocoding requests by making them public (rather than private), Avenue scripts-callable requests.

[data editing] The digital alignment of a satellite or aerial image with a map of the same area. In georectification, a number of corresponding control points, such as street intersections, … Read more

[coordinate systems] Aligning geographic data to a known coordinate system so it can be viewed, queried, and analyzed with other geographic data. Georeferencing may involve shifting, rotating, scaling, skewing, and … Read more

[data models] A geographic data model that represents geographic features as an interrelated set of spatial and attribute data. The georelational model is the fundamental data model used in coverages.

[data models] A geographic data model that represents geographic features as an interrelated set of spatial and attribute data. The georelational model is the fundamental data model used in coverages.

[Internet] Acronym for Geographically Encoded Objects for RSS feeds. Metadata for RSS documents that describes the location of Web content.

[IS technology] A set of technological approaches, such as GIS, photogrammetry, and remote sensing, for acquiring and manipulating geographic data.

[symbology] A model used to represent a real-world feature. For example, a geospecific model for the White House would look exactly like the White House and be used to represent … Read more

[astronomy] Positioned in an orbit above the earth’s equator with an angular velocity the same as that of the earth and an inclination and eccentricity approaching zero. A geostationary satellite … Read more

[ESRI software] A layer file created by the ArcGIS Geostatistical Analyst extension. It can be exported to ESRI GRID for further geoprocessing.

[statistics] A class of statistics used to analyze and predict the values associated with spatial or spatio-temporal phenomena. Geostatistics provides a means of exploring spatial data and generating continuous surfaces … Read more

[ESRI software] The software module in Survey Analyst – Cadastral Editor that manages the interaction between cadastral fabric jobs and the cadastral fabric.

[astronomy] Positioned in an orbit moving west to east with an orbital period equal to the earth’s rotational period. If a satellite is in a geosynchronous orbit that is circular … Read more

[symbology] A symbolic representation for a class of map features, such as government buildings. For example, on a map of the United States, a white building with a dome on … Read more

Acronym for Graphic Interchange Format. A low-resolution file format for image files, commonly used on the Internet. It is well-suited for images with sharp edges and reduced numbers of colors.

[ESRI software] In ArcSDE, a process that listens for client requests to connect to the database. When it receives such a request, it creates a connection by launching a gsrvr … Read more

[ESRI software] In Survey Analyst for field measurements, the single coordinate for a survey point that is the best overall representation for that survey point’s location, defined by one or … Read more

[ESRI software] An application used to manage data quality control, visually check data and run batch checks for attribute and geometry defects. Defects are recorded in an error table that … Read more

[ESRI software] The components of ArcGIS Server that host and run services. A GIS server consists of a server object manager and one or more server object containers.

[ocial context of GIS] Abbreviation for geographic information science. The field of research that studies the theory and concepts that underpin GIS. It seeks to establish a theoretical basis for … Read more

[data analysis] The computation of an output raster where the output value at each cell location may be a function of all the cells in the input raster.

[ESRI software] In Survey Analyst for field measurements, one of two ways to apply the Coordinate Out of Tolerance command. The Global Check method searches for coordinates out of tolerance … Read more

[ESRI software] A navigation mode in ArcGlobe during which the camera target is always at the center of the globe.

[spatial statistics use for geostatistics] In ArcGIS Geostatistical Analyst, a deterministic interpolation method. The interpolated surface is not required to conform to the sample data points, and the method does … Read more

[ESRI software] A field of type UUID (Universal Unique Identifier) in which values are automatically assigned by the geodatabase when a row is created. The GlobalID field is necessary for … Read more

1 [cartography] A sphere on which a map of the earth or a celestial body is represented. Since the earth’s natural shape is similar to a sphere, globes distort the … Read more

[ESRI software] A disk-based representation of the globe view or views contained in ArcGlobe. Globe documents have a .3dd extension.

[ESRI software] In ArcGlobe, properties that can be set for a globe document. These include vertical exaggeration, background color, or sun position.

[ESRI software] In ArcGlobe, a globe surface with base heights supplied from an elevation layer.

[ESRI software] In ArcGlobe, the display window in which a globe can be viewed.

[GPS] Acronym for Global Navigation Satellite System. The Russian counterpart of the United States Global Positioning System.

[symbology] The geometric shape of a character in a font.

[data transfer] Acronym for Geography Markup Language. An OpenGIS Implementation Specification designed to store and transport geographic information. GML is a profile (encoding) of XML.

[map projections] A planar projection, tangent to the earth at one point, projected from the center of the globe. All great circles appear as straight lines on this projection, so … Read more

In modeling, the degree to which a model predicts observed data; a measure of predictive power.