GIS Dictionary

[data models] A set of data elements arranged in rows and columns. Each row represents a single record. Each column represents a field of the record. Rows and columns intersect … Read more

[ESRI software] In ArcGIS, a tabbed list of data frames and layers (or tables) on a map that shows how the data is symbolized, the source of the data, and … Read more

A representation of tabular data for viewing and editing purposes. The table view created when a table is added to ArcMap is a copy of the actual table data stored … Read more

[data storage] Descriptive information, usually alphanumeric, that is stored in rows and columns in a database and can be linked to spatial data.

[defense] In MOLE, a type of graphic that aids in regulating the movement of force units, such as lane boundaries and obstacles.

1 [programming] In markup languages such as XML and HTML, a set of bracketed characters that define the structural purpose of a block of content. 2 [computing] A keyword used … Read more

[programming] A pair of keywords used to set additional properties for elements that are not part of the UML specification, such as the point, line, and polygon geometry of a … Read more

A projection whose surface touches the globe’s without piercing it. A tangent planar projection touches the globe at one point, while tangent conic and cylindrical projections touch the globe along … Read more

[ESRI software] In ArcScene and ArcGlobe, the center point in a scene’s view at which the camera is aimed.

[computing] A computer to which an application is deployed.

[ESRI software] In an editing session prior to ArcGIS 10, the layer to which edits will be applied. In ArcGIS versions 9 and earlier, the target layer must be specified … Read more

[ESRI software] In ArcScene and ArcGlobe, the height of a target point above a surface used when calculating lines of sight and viewsheds.

[ESRI software] In ArcView 3.x, the theme from which features are selected during a theme-on-theme selection operation. Multiple target themes may be specified for a theme-on-theme selection.

[ESRI software] In ArcGIS Explorer and ArcGIS Server, a user interface combined with a particular piece of GIS functionality in a format that can be easily added to applications. Tasks … Read more

Acronym for Transmission Control Protocol/Internet Protocol. The most common protocol for Internet traffic. The Transmission Control Protocol (TCP) is a communication protocol layered above the Internet Protocol (IP), which is … Read more

[data structures] Data that specifically refers to times or dates. Temporal data may refer to discrete events, such as lightning strikes; moving objects, such as trains; or repeated observations, such … Read more

[ESRI software] In ArcGIS Tracking Analyst, a type of event used to describe observations through time of particular objects or groups of objects.

[ESRI software] All the temporal information, including the earliest and last observations, of a data layer in ArcGIS Tracking Analyst.

[data models] An emerging capability in GIS for integrating temporal data with location and attribute data.

[ESRI software] In ArcGIS Tracking Analyst, an object being observed through time.

[ESRI software] The component of a complex temporal event in ArcGIS Tracking Analyst that contains feature shape and attribute information.

[ESRI software] In ArcGIS Tracking Analyst, data gathered for a given object through time.

[ESRI software] The component of a complex temporal event in ArcGIS Tracking Analyst that contains feature attribute information, and possibly time and date information.

[ESRI software] A function in ArcGIS Tracking Analyst that allows users to play back the temporal display of data as if it had occurred at a user-defined date and time. … Read more

[ESRI software] In ArcGIS Tracking Analyst, the time range within which data will be displayed. Temporal windows can be set at the layer level on the Symbology tab.

[data storage] A dataset temporarily stored on disk or in memory.

[geography] An area of land having a particular characteristic, such as sandy terrain or mountainous terrain.

[3D GIS] A multiresolution, TIN-based surface built from measurements stored as features in a geodatabase. Associated and supporting rules help organize the data and control how features are used to … Read more

[3D GIS] A data structure associated with a terrain dataset used to define a multi-resolution surface, which organizes data into different levels of detail, or pyramid levels, and serves to … Read more

[3D GIS] In a terrain dataset, a collection of line or polygon feature classes used to represent those geographic features at different levels of detail.

[3D GIS] An individual level of detail in a terrain dataset pyramid. Each level has a pair of properties: resolution and scale. The resolution defines the amount of detail represented … Read more

[3D GIS] The range of pyramid levels for which polygon or polyline features will be enforced in the surface of a terrain dataset.

[3D GIS] A spatially coherent organization of terrain data facilitating efficient retrieval and editing. Tile definition is based on the average point spacing of the source data.

[data structures] The division of a two-dimensional area into polygonal tiles, or a three-dimensional area into polyhedral blocks, in such a way that no figures overlap and there are no … Read more

[ESRI software] A table containing text attributes, such as color, font, size, location, and placement angle, for an annotation subclass in a coverage. In addition to user-defined attributes, the text … Read more

[software] An entity that displays text entered by a user or derived from another source for editing purposes.

[ESRI software] A rectangle that bounds a text string.

[ESRI software] Tags used with text in ArcGIS that allow formatting to be modified for a portion of a text string. This allows the creation of mixed-format text where, for … Read more

[cartography] Text placed next to a feature on a map to describe or identify it.

[symbology] A text style defined by font, size, character spacing, color, and so on, used to label maps and geographic features.

[3D GIS] A digital representation of the surface of a feature.

[ESRI software] In ArcScene and ArcGlobe, a location embedded in a geometry that helps define how a texture is mapped.

[ESRI software] The application of a texture to a 3D object in ArcScene and ArcGlobe.

[data structures] Features of one type that are generally placed together in a single layer.

[map design] A map designed to convey information about a single topic or theme, such as population density or geology.

[ESRI software] In ArcView 3.x, a set of related geographic features such as streets, parcels, or rivers, along with their attributes. All features in a theme share the same coordinate … Read more

[ESRI software] In ArcView 3.x, a document object linked to the set of features in a theme. It serves as an interface to the underlying database, allowing manipulation of the … Read more

[ESRI software] In ArcView 3.x, an operation in which features in one theme are selected based on their spatial relationships with features in another theme. Theme-on-theme selection is used to … Read more

[surveying] A surveying instrument for measuring vertical and horizontal angles, consisting of an alidade, a telescope, and graduated circles mounted vertically and horizontally.

[Euclidean geometry] Polygons generated from a set of sample points. Each Thiessen polygon defines an area of influence around its sample point, so that any location inside the polygon is … Read more

[database structures] The third level of guidelines for designing table and data structures in a relational database. The third-normal-form guideline incorporates the guidelines of first and second normal form; in … Read more

[software] A process flow through an application. An application can have many threads.

[software] A software configuration in which three software applications (commonly a client program, application server, and database server) work together to accomplish a task.

In business analysis, an operation that creates rings that contain a given population around a store or stores on a map.

1 [graphics computing] A miniaturized version of a graphics file. A thumbnail can be used as a visual index for larger data or images. 2 [ESRI software] In ArcGIS, a … Read more

[ESRI software] A registration or geographic control point for a coverage representing a known location on the earth’s surface. Tics allow all coverage features to be recorded in a common … Read more

1 [symbology] Graphics that mark divisions of measurement on a scale bar. 2 [graphics map display] Short, regularly spaced lines along the edge of an image or neatline that indicate … Read more

[geodesy] A vertical datum in which zero height is defined by a particular tidal surface, often mean sea level. Examples of tidal surfaces include mean sea level, mean low water … Read more

[surveying] A point whose location is determined by a tie survey. [photogrammetry] A point in a digital image or aerial photograph that represents the same location in an adjacent image … Read more

[surveying] A survey that uses a point of known location on the ground to determine the location of a second point.

[geocoding] In geocoding, two or more records that yield the same score when matching an address.

[database structures] Acronym for Topologically Integrated Geographic Encoding and Referencing. The nationwide digital database developed for the 1990 census, succeeding the DIME format. TIGER files contain street address ranges, census … Read more

A digital database of geographic features, covering the entire United States and its territories, that provides a topological description of the geographic structure of these areas. The files are a … Read more

A high or complex degree of interconnections between the components within a program or between programs, that requires substantial overlap between methods, ontologies, class definitions, and so on.

[data structures] An internal subsetting of a spatial dataset (commonly raster) into a manageable rectangular set, or rows and columns of pixels, typically used to process or analyze a large … Read more

[ESRI software] One of two methods for displaying temporal data in ArcGIS Tracking Analyst: real-time mode or playback mode. Time modes are determined by the use of the Tracking Analyst … Read more

[network analysis] In networks, the time during which a stop can be visited. For example, on a bus route, each stop may have a time window of 15 minutes. If … Read more

[ESRI software] In ArcGIS Network Analyst, a time window violation occurs when a route arrives at a network location after its associated time window has closed.

Acronym for triangulated irregular network. A vector data structure that partitions geographic space into contiguous, nonoverlapping triangles. The vertices of each triangle are sample data points with x-, y-, and … Read more

[data structures] A dataset containing a triangulated irregular network (TIN). The TIN dataset includes topological relationships between points and neighboring triangles.

[ESRI software] A layer that references a set of TIN data. TIN data contains a triangulated irregular network (TIN) and includes topological relationships between points and neighboring triangles.

One of four types of edges that may be found in a TIN: regular lines, hard breaklines, soft breaklines, and outside lines. Regular lines define the TIN’s basic structure, connecting … Read more

[map projections] A graphical representation of the spatial distortion at a particular map location. The indicatrix is the figure that results when a circle on the earth’s surface is plotted … Read more

[cartography] Acronym for topographic line map. A map that uses line contours to show elevations and depressions of the earth’s surface. Topographic line maps may be used to portray topography, … Read more

[programming] Acronym for thread neutral apartment. An apartment that has no threads permanently associated with it; threads enter and leave the apartment as required.

Of an arc’s two endpoints, the last one digitized. From- and to-nodes give an arc left and right sides and, therefore, direction.

[geography] A formulation of the concept of spatial autocorrelation by the geographer Waldo Tobler (1930-), which states “Everything is related to everything else, but near things are more related than … Read more

[ESRI software] A line of encrypted code generated by an authenticating service that allows a client to access a Web service. In ArcWeb Services, a token must be regenerated by … Read more

[data editing] The minimum or maximum variation allowed when processing or editing a geographic feature’s coordinates. For example, during editing, if a second point is placed within the snapping tolerance … Read more

1 [software] A command that requires interaction with the GUI before an action is performed. For example, a zoom tool requires a user to use the mouse to click on … Read more

[software] A graphical user interface (GUI) with buttons that allow users to execute software commands.

[ESRI software] In ArcGIS, an object that contains toolsets and geoprocessing tools. It takes the form of a .tbx file on disk, or a table in a geodatabase.

[ESRI software] In ArcToolbox (part of ArcGIS 8.3 and earlier versions), a hierarchical view of toolsets and tools grouped by functionality.

[programming] An application that software developers can use with their integrated development environment (IDE) to make programming easier. For example, SOAP toolkits allow users to interact with SOAP Web services … Read more

[ESRI software] In ArcGIS, a group of geoprocessing tools that perform similar tasks.

[software] The description of a tool or control that is displayed on screen when the mouse is paused over it.

A map that represents the vertical and horizontal positions of features, showing relief in some measurable form, such as contour lines, hypsometric tints, and relief shading.

[cartography] The study and mapping of land surfaces, including relief (relative positions and elevations) and the position of natural and constructed features.

[ESRI software] The spatial relationship between features that share geometry such as boundaries and vertices. When a boundary or vertex shared by two or more features is edited using the … Read more

[ESRI software] A feature that supports network connectivity that is established and maintained based on geometric coincidence.

1 [ESRI software] In geodatabases, the arrangement that constrains how point, line, and polygon features share geometry. For example, street centerlines and census blocks share geometry, and adjacent soil polygons … Read more

[ESRI software] A temporary collection of edges and nodes used in ArcMap to query and edit the topological coincidence between features. The cache is built for the current display extent … Read more

[ESRI software] In ArcMap, a predefined method for correcting topology errors. For example, predefined topology fixes for a dangling line include snapping, trimming, or extending to another line.

[ESRI software] An instruction to the geodatabase defining the permissible relationships of features within a given feature class or between features in two different feature classes.

[geography] A place-name.

[ESRI software] In ArcInfo Workstation, a network solver that determines the minimum-cost path to reach a series of stops, and also determines the order in which the stops are visited.

1 [cadastral and land records] In the United States, a quadrangle approximately 6 miles on a side, bounded by meridians and parallels and containing 36 sections. 2 [local government] A … Read more

[ESRI software] In Survey Analyst for field measurements, an entry in an electronic or paper field book that represents observations from a theodolite. A slope distance, vertical angle, horizontal angle, … Read more

[ESRI software] In Survey Analyst for field measurements, a group of field book entries that belong together define a single setup of the instrument. Each observation (slope distance, vertical angle, … Read more

1 [ESRI software] In ArcMap, ArcScene, and ArcGlobe, an ordered collection of similar keyframes that, when played as an animation, shows a dynamic transition between them. 2 [ESRI software] In … Read more