GIS Dictionary

[software] A ready-to-use Web application that is designed for a specific purpose, such as a store locator or a map viewer. Starter applications do not require customization before use.

1 [programming] In programming, the current data contained by an object. 2 [government] An autonomous political and administrative division of geography. The United States is composed of 50 states. 3 … Read more

[coordinate systems] A group of planar coordinate systems based on the division of the United States into more than 130 zones to minimize distortion caused by map projections. Each zone … Read more

[ESRI software] A logical organization of all the states in the geodatabase. A state tree illustrates and maintains the logical relationship between states of a versioned geodatabase.

[programming] In programming, an operation that makes changes to an object or one of its associated objects, such as removing a layer from a map.

[programming] In programming, not retaining changes between calls. A stateless object or application does not store parameters or values from the last time it was called, so it is always … Read more

[programming] An operation that does not make changes to an object, such as drawing a map.

[GPS] Determining a position on the earth by averaging the readings taken by a stationary antenna over a period of time.

[spatial statistics use for geostatistics] In geostatistics, a property of a spatial process in which all statistical properties of an attribute depend only on the relative locations of attribute values.

[linear referencing] In the pipeline industry, another name for linear referencing. Stationing allows any point along a line feature representing a pipeline to be uniquely identified by its relative position … Read more

[statistics] Ordinal, interval, or ratio data represented as a surface in which the height of each area is proportional to a numerical value.

[network analysis] A line that follows the steepest downhill direction on a surface. Paths terminate at the surface perimeter or in surface concavities or pits.

[Euclidean geometry] The solid (conical) angle subtended at the center of a sphere of radius r by a bounded region on the surface of the sphere having an area r … Read more

[map design] A map produced with a stereoscopic plotter using aerial photographs and geodetic control data.

1 [map projections] A tangent planar projection that views the earth’s surface from a point on the globe opposite the tangent point. 2 [map projections] A secant planar projection that … Read more

[photogrammetry] A stereoscope containing a micrometer for measuring the effects of parallax in a stereoscopic image.

[photogrammetry] The three-dimensional image formed where rays from points in the images of a stereoscopic pair intersect.

[photogrammetry] Two aerial photographs of the same area taken from slightly different angles that when viewed together through a stereoscope produce a three-dimensional image.

[photogrammetry] An instrument that projects a stereoscopic image from aerial photographs, converts the locations of objects and landforms on the image to x-, y-, and z-coordinates, and plots these coordinates … Read more

[photogrammetry] A binocular device that produces the impression of a three-dimensional image from two overlapping images of the same area.

[ESRI software] When editing in ArcMap, a setting that defines the minimum number of pixels the pointer must move on the screen before a selected feature is moved.

1 [modeling] A model that includes a random component. The random component can be a model variable, or it can be added to existing input data or model parameters. 2 … Read more

[ESRI software] In ArcGIS Network Analyst, a network location used to determine a route in route analysis. Users can specify multiple stops, of which two must be used to represent … Read more

[network analysis] In network analysis, the time it takes for a stop to occur, used to compute the impedance of a path or tour. For example, when a school bus … Read more

[database structures] A set of parameters that specify how data and indexes are stored in an ArcSDE database. Keywords are stored in a table in the ArcSDE database.

[analysisgeoprocessing] A type of business analysis that uses mostly data about a store or stores, rather than about customers. Examples include ring studies and analyses of equal competition areas and … Read more

A type of business analysis that assesses the potential of a site by performing simple ring or drive-time analysis.

[ESRI software] An ArcGIS Spatial Analyst function that identifies which cells belong to which source, based on closest proximity in a straight line.

[ESRI software] An ArcGIS Spatial Analyst function that identifies the azimuth direction from each cell to the nearest source.

[ESRI software] An ArcGIS Spatial Analyst function that calculates the distance in a straight line from every cell to the nearest source.

[importexport] A mode of data delivery in which objects provide data storage. Stream objects can contain any type of data in any internal structure.

[data capture] A method of digitizing in which, as the cursor is moved, points are recorded automatically at preset intervals of either distance or time.

[data capture] During stream mode digitizing, the minimum interval between vertices. Stream tolerance is measured in map units.

[importexport] A technique for transferring data, usually over the Internet, in a real-time flow as opposed to storing it in a local file first. Streaming allows large multimedia files to … Read more

[network analysis] A system of interconnecting lines and points that represent a system of roads for a given area. A street network provides the foundation for network analysis; for example, … Read more

[address matching] A form of digital mapping that links information to geographic locations and displays address locations as point features on a map.

[visualization] A display technique applied to the histogram of raster datasets, most often used to increase the visual contrast between cells.

1 [data structures] A set of coordinates that defines a group of linked line segments. 2 [programming] A sequence of letters or numbers, or both, sometimes with a fixed length.

[3D analysis] A line feature enforced in a TIN. There are two types of structure lines: hard and soft. Hard structure lines, also known as breaklines, represent interruptions in the … Read more

[analysisgeoprocessing] The geographic area treated in an analysis.

[cartography] An organized collection of predefined colors, symbols, properties of symbols, and map elements. Styles promote standardization and consistency in mapping products.

[ESRI software] The tool used to create new styles and edit existing ones. The Style Manager displays the contents of all the styles that are currently referenced by the map. … Read more

[Internet] A file or form that provides style and layout information, such as margins, fonts, and alignment, for tagged content within an XML or HTML document. Style sheets are frequently … Read more

[programming] In ArcGIS, a subset of all the fields associated with a layer or data.

[empty] (Pronounced “smee”) This person is usually from Development or Products who specializes in the software, workflow, or subject matter on which the course is based.

[ESRI software] One of several layers that are part of a group layer in a map document.

[ESRI software] Within a geometric network, the replacement of an orphan junction by a non-orphan junction from a user-defined feature class. The original junction is deleted from the network, and … Read more

[graphics computing] In printing, the three primary colorscyan, magenta, and yellowthat when used as filters for white light remove blue, green, and red light, respectively.

[database structures] In geodatabases, a subset of features in a feature class or objects in a table that share the same attributes. For example, the streets in a streets feature … Read more

[modeling] A model that weights locations relative to each other based on given criteria. Suitability models might aid in finding a favorable location for a new facility, road, or habitat … Read more

[cartography] A contour line placed between regularly spaced contours, used when the terrain change is not large enough to be depicted with consistent contour intervals.

[data models] A geographic phenomenon represented as a set of continuous data (such as elevation, geological boundaries, or air pollution); a spatial distribution which associates a single value with each … Read more

[spatial statistics use for geostatistics] Generating a statistical surface that approximates the values of a set of known x,y,z points.

[ESRI software] Perpendicular or normal to the slope of the surface in 3D Analyst. As changes in slope are approached across the surface, the degree of smoothness is defined by … Read more

[ESRI software] In Survey Analyst for field measurements, a collection of survey objects of a particular type. A survey dataset contains a set of survey classes for each of the … Read more

[ESRI software] In Survey Analyst for field measurements, importers that interpret operation codes and feature codes when a data collector file is imported. Users choose the converter that matches the … Read more

[ESRI software] In Survey Analyst for field measurements, a dataset that stores survey objects.

[ESRI software] In Survey Analyst for field measurements, the main interface for working with stored survey information. Data may be explored and edited directly in the Survey Explorer. Users can … Read more

[ESRI software] In Survey Analyst for field measurements, layers that are created whenever survey datasets or survey projects are added to the map. Survey layers appear in the table of … Read more

[ESRI software] An object, such as a metal disk, permanently mounted in the landscape to denote a survey station.

[ESRI software] In Survey Analyst for field measurements, a collective term referring to measurements, computations, survey points, and coordinates in the survey dataset.

[ESRI software] In Survey Analyst for field measurements, named locations that are observed through various surveys. Survey points can be observed multiple times and by many surveys over time. They … Read more

[ESRI software] In Survey Analyst for field measurements, a subset of the survey dataset that represents a unit of work. A survey project is used as a logical structure that … Read more

[surveying] A location on the earth that has been accurately determined by geodetic survey.

[ESRI software] In Survey Analyst for field measurements, the feature classes in the geodatabase that contain survey-aware features.

[ESRI software] In Survey Analyst for field measurements, features that are associated with survey data.

[surveying] Measuring physical or geometric characteristics of the earth. Surveys are often classified by the type of data studied or by the instruments or methods used. Examples include geodetic, geologic, … Read more

[graphics computing] Acronym for scalable vector graphics. An XML-based graphics file format that describes two-dimensional vector images, including animation. SVG images scale to fit the display window without compromising quality.

[data structures] A vector-based Flash file format that supports text, audio, video, and end-user interaction. SWF files are often used to publish animations on the Web.

[data structures] Scene document. A document saved by ArcScene that has an .sxd extension.

[database structures] A commercial RDBMS.

[symbology] A graphic used to represent a geographic feature or class of features. Symbols can look like what they represent (trees, railroads, houses), or they can be abstract shapes (points, … Read more

[defense] A 15-character identifier that provides the information necessary to display or transmit a tactical symbol between MIL-STD-2525B compliant systems.

[ESRI software] In ArcGIS, a setting that determines the drawing order of features based on their symbol. When symbols have more than one layer, symbol level drawing can be used … Read more

[symbology] A collection of symbols.

[ESRI software] In MOLE, a defined area in which optional text or graphics may be entered to provide additional information about a force element or tactical graphic.

[symbology] The process of devising a set of marks of appropriate size, color, shape, and pattern, and assigning them to map features to convey their characteristics at a given map … Read more

The set of conventions, rules, or encoding systems that define how geographic features are represented with symbols on a map. A characteristic of a map feature may influence the size, … Read more

1 [ESRI software] In geodatabase editing, the process of applying changes made from a replica to the relative replica in a replica pair. 2 [database structures] The process of automatically … Read more

1 [ESRI software] In geodatabase editing, the geodatabase version that receives changes during synchronization. The synchronization version is always a child of the replica version. With one-way and two-way replication, … Read more

1 [physics] Occurring together, or at the same time. 2 [data transfer] In data transmission, precisely timed and steady transmission of information that allows for higher rates of data exchange. … Read more

[programming] The structural rules for using statements in a command or programming language.

[ESRI software] In ArcGIS, a geoprocessing tool. System tools are stored in system toolsets and can be copied to custom toolsets and/or toolboxes.

[ESRI software] In ArcGIS, a default geoprocessing toolbox that is installed with ArcGIS. System toolboxes contain system tools, organized into toolsets for ease of access.

[ESRI software] In ArcGIS, a subset of a geoprocessing toolbox that holds system tools.

[ESRI software] In Survey Analyst, one type of measurement error. Systematic error follows a mathematical or physical law, and it can be corrected to comply with a known standard.