GIS Dictionary

[computing] A template for an object that can be instantiated in memory.

[GPS] GPS measurements calculated using the PRN code transmitted by a GPS satellite.

[ESRI software] A type of attribute domain that defines a set of permissible values for an attribute in a geodatabase. A coded value domain consists of a code and its … Read more

1 [coordinate geometry COGO] Acronym for coordinate geometry. A method for calculating coordinate points from surveyed bearings, distances, and angles. 2 [coordinate geometry COGO] Automated mapping software used in land … Read more

[ESRI software] In Survey Analyst for field measurements, measurements that comprise a set of interdependent COGO simple measurements.

[ESRI software] In Survey Analyst for field measurements, measurements that model values that define vectors, directions, lengths, and orthogonal offsets.

[Euclidean geometry] Occupying the same space. Coincident features or parts of features occupy the same space in the same plane.

[ESRI software] In a geodatabase, how the coordinates of coincident features are stored. For example, if two lines are coincident, they will both be drawn in ArcMap, with one line … Read more

A form of kriging in which the distribution of a second, highly correlated variable (covariate) is used along with the primary variable to provide interpolation estimates. Cokriging can improve estimates … Read more

[non-ESRI software] An Adobe software product that integrates databases and Web pages using a server and development tools. ColdFusion Web pages include elements written in ColdFusion Markup Language that simplify … Read more

[ESRI software] An ArcIMS Application Server Connector. In this environment, a request that includes ColdFusion tags is first executed on the ColdFusion Server. The ArcIMS custom ColdFusion tags are then … Read more

[remote sensing] A color image made by assigning red, green, and blue colors to each of the separate monochrome bands of a multispectral image and then superimposing them.

[graphics computing] A set of values that are associated with specific colors. Color maps are most commonly used to display a raster dataset consistently on many different platforms.

[graphics computing] Any system that organizes colors according to their properties for printing or display. Examples include RGB (red, green, blue), CMYK (cyan, magenta, yellow, black), HSB (hue, saturation, brightness), … Read more

[symbology] A range of colors used to show ranking or order among classes on a map.

1 [printing] In printing, the use of a separate printing plate for each ink color used. 2 [printing] The process of scanning with color filters to separate the original image … Read more

1 [database structures] An item in an attribute table. 2 [computing] The vertical dimension of a table. Each column stores the values of one type of attribute for all the … Read more

[computing] Acronym for Component Object Model. A binary standard that enables software components to interoperate in a networked environment regardless of the language in which they were developed. Developed by … Read more

[programming] The COM requirement that interfaces, once published, cannot be altered.

[programming] A grouping of logically related virtual functions, implemented by a server object, allowing a client to interact with the server object. Interfaces form the basis of COMs communication between … Read more

[mathematics] A kind of mathematical operator that interprets input with Boolean values. Combinatorial operators assign a different number to each unique combination of input values.

[computing] A user interface tool that combines the features of a text box and a drop-down list. For example, the Location combo box in ArcCatalog allows the selection of an … Read more

1 [computing] An instruction to a computer program, usually one word or concatenated words or letters, given by the user from a control device, such as a keyboard, or read … Read more

[ESRI software] A toolbar, menu bar, menu, or shortcut menu in an ArcGIS application.

[computing] A string of text that acts as a command, typed at an interface prompt.

[computing] A format of the input and output of a program in which the user enters commands by means of strings of text typed on a keyboard, as opposed to … Read more

[ESRI software] In geoprocessing, a window that provides a command line for running tools and a message window for viewing the status messages created when running those tools.

[non-ESRI software] A window accessible from the Windows Start menu in which MS-DOS commands are typed.

1 [ESRI software] In Survey Analyst for field measurements, a field that provides additional information about the computation. 2 [programming] One or more specially marked lines of text used to … Read more

[ESRI software] The isolation level in a database management system (DBMS) in which transactions read committed data only they don’t read data that has not been committed.

[ESRI software] A process that rearranges and consolidates the data in a file so that it occupies a single, contiguous space, allowing the data in each file to be accessed … Read more

[computing] The degree of uncertainty that can be tolerated in the spelling of a keyword used in a search, including phonetic errors and the random insertion, deletion, replacement, or transposition … Read more

[navigation] An instrument used to find the direction of north from one’s current location, consisting of a case with compass points marked around its edge and a floating magnetic needle … Read more

[cartography] An indication of direction. One of the 32 divisions into which the circle around the needle of a compass is divided, each equal to 11.25 degrees.

[symbology] A diagram of compass points drawn on a map or chart, subdivided clockwise from 0 to 360 degrees with 0 indicating true north. On older maps and charts a … Read more

1 A widely used rule for adjusting a traverse that assumes the precision in angles or directions is equivalent to the precision in distances. This rule distributes the closure error … Read more

[programming] A program used in software development that translates the lines of a programmer’s code from one programming language to another, usually from a high-level language to the ones and … Read more

[ESRI software] In ArcGIS Tracking Analyst, a type of complex temporal event that includes two components and involves a moving object, such as an airplane. The moving object’s geographical location … Read more

[ESRI software] In a geodatabase, a linear network feature that corresponds to one or more network elements in the logical network.

[ESRI software] In ArcGIS 8.3 and previous versions, a junction feature in a geodatabase that corresponds to more than one network element in the logical network. For example, the state … Read more

[data analysis] An area calculated by finding the outermost customers of a store along several vectors and connecting them. Complex market areas are more accurate than simple market areas because … Read more

[ESRI software] A type of complex temporal event in ArcGIS Tracking Analyst that includes two components and involves a stationary object, such as a traffic sensor. The sensor’s geographical location … Read more

[ESRI software] An event in ArcGIS Tracking Analyst that contains two components: one with persistent object information, and one with observations of the object through time. The merger of the … Read more

[non-ESRI software] In COM, a binary unit of code that can be used to create COM objects.

[computing] A section of the registry that can be used to categorize classes by their functionality. Component categories are used extensively in ArcGIS to allow extensibility of the system.

[ESRI software] An ArcGIS utility program (Categories.exe) that can be used to view and manipulate component category information.

[ESRI software] In Survey Analyst for field measurement, a set of simple measurements that are related and applied as a group.

[computing] A link or association between objects where the lifetime of one object controls the lifetime of its related objects. For example, the association between a highway and its shield … Read more

[computing] A UML term used to describe a form of association in which the lifetime of the whole controls the lifetime of the parts. In a composition, the instances of … Read more

[standards] Within metadata, a group of data elements (including other compound elements) that together describe a characteristic of a spatial dataset in more detail than can be described by an … Read more

[database structures] A primary key that requires two or more fields to be unique.

[computing] The process of reducing the size of a file or database. Compression improves data handling, storage, and database performance. Examples of compression methods include quadtrees, run-length encoding, and wavelets. … Read more

[map projections] A projection that does not have equal area, conformal, or equidistant characteristics. The compromise projection is an attempt at balance between these characteristics, and is often used in … Read more

[ESRI software] In Survey Analyst for field measurements, a process that requires a set of input parameters to apply a set of rules, and an algorithm to calculate output parameters. … Read more

[ESRI software] In Survey Analyst for field measurements, a unique identifier that calls or retrieves a specific type of computation, defined on the General tab of the Survey Explorer.

[ESRI software] In Survey Analyst for field measurements, a sequence of computation dependenciesthe output points of some computations are used as the input for one or more others.

[ESRI software] In Survey Analyst for field measurements, the condition of a computation. A computation may be in four different states: valid, out-of-date, incorrect, or incomplete.

[ESRI software] In Survey Analyst for field measurements, a tool that interacts with the map to add measurement values to computation pages.

[mathematics] A branch of mathematics that uses algorithms to solve geometry problems. Computational geometry is used in many GIS operations, including proximity analysis, feature generalization, and automated text placement.

[education] Instruction or training that uses computer-based media instead of hard-copy materials. Computer-assisted learning is generally designed to use the strengths of computer-based media such as the ability to navigate … Read more

[computing] To join two or more character strings together, end to end; for example, to combine the two strings “spatial” and “analysis” into the single string “spatial analysis.”

[ESRI software] In linear referencing, a command that combines event records in tables containing events on the same route with the same value for specified fields. Only events in situations … Read more

[computing] In a relational database table, a primary key made by combining two or more keys that together form a unique identifier.

[ESRI software] The ability of a DBMS to support simultaneous access by more than one user.

[data editing] A database management process for maintaining the consistency of data while supporting simultaneous editing by more than one user. A typical technique involves locking portions of the database … Read more

[computing] Floating software products that are administered by a license manager. A central license manager (installed anywhere on a network) allows users to install the floating products on any number … Read more

[ESRI software] A component of the PLTS knowledge base that contains SQL statements and custom code for feature validation extended beyond standard geodatabase domains. PLTS utilizes condition tables for enhanced … Read more

[computing] A symbol or keyword that specifies the relationship between two values and is used to construct queries to a database. Examples include = (equal to), < (less than), and ... Read more

[computing] A programming language statement that executes one option if the statement is true, and another if it is false. The if-then-else statement is an example of a conditional statement.

1 [ESRI software] In ArcIMS, the file that contains the core site information. ArcIMS configuration files contain all the basic information about the content to be delivered, such as location … Read more

[ESRI software] In ArcSDE, a name for a group of parameters that defines how geodatabase objects are stored.

[data editing] A set of procedures that aligns the features of two geographic data layers and then transfers the attributes of one to the other.

[data editing] In database editing, a state of incompatibility that occurs when multiple users simultaneously edit a version or reconcile two versions. Conflicts occur when the same feature or topologically … Read more

1 [data editing] The process of solving uncertainty within a database that occurs when two versions of the same data are edited at the same time. Conflicts can occur when … Read more

A projection that preserves the correct shapes of small areas. In a conformal projection, graticule lines intersect at 90-degree angles, and at any point on the map the scale is … Read more

The characteristic of a map projection that preserves the shape of any small geographic area.

A projection that transforms points from a spheroid or sphere onto a tangent or secant cone that is wrapped around the globe in the manner of a party hat. The … Read more

[ESRI software] In ArcCatalog, a mechanism used to access remote file systems and shared databases.

[cadastral and land records] A cadastral fabric line with bearing and distance data attached to it, commonly used to tie parcels across roads, tie in control points, or tie the … Read more

1 [data models] The way in which features in GIS data are attached to one another functionally or spatially. 2 [ESRI software] In a geodatabase, the state of association between … Read more

[network analysis] In network datasets, a logical grouping of point features, line features, or both, that controls how network elements are connected. Connectivity groups are defined when a network dataset … Read more

[network analysis] In a network dataset, a property of network sources that defines how network elements connect to each other within a connectivity group. There are two types of edge-edge … Read more

[data models] A visual representation of the relationship between elements in a model. Connectors join elements together to create processes. Typical processes connect an input data element, a tool element, … Read more

[ESRI software] In Survey Analyst for field measurements, one of two phases involved when performing a least squares adjustment for a measurement network. In this phase, the emphasis is on … Read more

[data models] Limits imposed on a model to maintain data integrity. For example, in a water network model, an 8-inch pipe cannot connect to a 4-inch pipe.

[ESRI software] In ArcGIS versions 9 and earlier, an edit command that takes selected features from one or more feature classes and creates new features in a target feature class. … Read more

[ESRI software] In Survey Analyst – Cadastral Editor, a line with a bearing and distance that is used to create geometry for a new cadastral fabric parcel.

[ESRI software] The operating system account that server object container processes run as, which is specified by the GIS server postinstallation utility. Objects running in a server container process have … Read more

[ESRI software] A process in which one or more server objects are running. Container processes run on SOC machines, and are started and shut down by the SOM. They are … Read more

A spatial relationship in which a point, line, or polygon feature or set of features is enclosed completely within a polygon.

[Internet] In ArcGIS Online, refers to maps, layers, and tools.

[standards] A publication authored by the FGDC that specifies the information content of metadata for digital geospatial datasets. The purpose of the standard is to provide a common set of … Read more

Having the same or coincident boundaries.

A list menu that pops up when the right mouse button is clicked in Windows applications. Some keyboards also have an application key that opens shortcut menus.

In a coverage, the topological identification of adjacent polygons by recording the left and right polygon for each arc.

1 [data structures] Of polygons: adjacent; having a common boundary; sharing an edge. 2 [data structures] Of raster cells: connected orthogonally or diagonally; or, sometimes, connected strictly orthogonally. 3 [data … Read more

[data models] Data such as elevation or temperature that varies without discrete steps. Since computers store data discretely, continuous data is usually represented by TINs, rasters, or contour lines, so … Read more

[data models] A feature that is not spatially discrete. The transition between possible values on a continuous surface is without abrupt or well-defined breaks.

[data models] A raster in which cell values vary continuously to form a surface. In a continuous raster, the phenomena represented have no clear boundaries. Values exist on a scale … Read more

[printing] A photograph that has not been screened and so displays all the varying tones from dark to light.