GIS Dictionary

[navigation] Acronym for International Civil Aviation Organization. A member organization that represents the worldwide body of nations for standardizing flight rules, regulations, and requirements.

[ESRI software] In MOLE, the innermost graphic component of a graphic. Icons represent the Function ID position of a Symbol ID code.

[empty] An ID assists with the design and flow of the course, helping the author with the organization of the content, determining the best way to present a particular concept, … Read more

[programming] Acronym for interface identifier. A string that provides the unique name of an interface. An IID is a type of globally unique identifier (GUID).

[programming] Acronym for integrated development environment. A software development tool for creating applications, such as desktop and Web applications. IDEs blend user interface design and layout tools with coding and … Read more

[computing] A unique character string or numeric value associated with a particular object.

[ESRI software] In ArcGIS, a tool that, when applied to a feature (by clicking it), opens a window showing that feature’s attributes.

[analysisgeoprocessing] In geoprocessing, a topological overlay that computes the geometric intersection of two datasets. The output dataset preserves all the features of the first dataset plus those portions of the … Read more

[data editing] An anchor that prevents the movement of features during rubber sheeting.

[non-ESRI software] A generic COM interface that has methods allowing clients to ask which members are supported. Classes that implement IDispatch can be used for late binding and DispID binding, … Read more

[programming] Acronym for Interface Definition Language. A language used to define COM interfaces. The Microsoft implementation of IDL may also be referred to as MIDL or Microsoft IDL.

[remote sensing] Acronym for interferometric synthetic aperture radar. A dual-antenna radar sensor mounted on an airborne or space-borne platform that collects a remotely sensed radar image, called an interferogram. There … Read more

[cartography] The light incident on a surface or object, either natural or artificial, as determined by the surface’s slope and aspect and by the sun’s azimuth and altitude.

1 [data capture] A representation or description of a scene, typically produced by an optical or electronic device, such as a camera or a scanning radiometer. Common examples include remotely … Read more

[data structures] An x,y coordinate pair specifying the location of a pixel, or cell, in terms of its row and column position. The x-coordinate gives the column number (commonly starting … Read more

[data capture] Data produced by scanning a surface with an optical or electronic device. Common examples include scanned documents, remotely sensed data (for example, satellite images), and aerial photographs. An … Read more

A digital image processing technique for increasing the contrast between features in an image by dividing the pixel values in the image by the values of corresponding pixels in a … Read more

[data capture] The ratio between a distance in an image and the actual distance on the ground, calculated as focal length divided by the flying height above mean ground elevation. … Read more

1 [ESRI software] In ArcGIS Server, an extension. 2 [ESRI software] In ArcIMS, a public ArcIMS virtual server for image services

1 [ESRI software] In ArcIMS, a service that uses the spatial server image rendering capabilities. When a request is received, a map is generated on the server, and the response … Read more

[ESRI software] In ArcGIS Image Server, a workspace created using the Image Service Definition Editor toolbar that defines the key properties of a service, including name and default spatial reference … Read more

[ESRI software] In ArcGIS Image Server, a file that stores properties for reestablishing a connection to a service and setting up user-defined image service properties. Image service reference files have … Read more

[data structures] The x,y coordinate space defined by the number of columns and rows in a raster dataset. The origin of image space is commonly the center of the top … Read more

[network analysis] A measure of the amount of resistance, or cost, required to traverse a path in a network, or to move from one element in the network to another. … Read more

[ESRI software] In ArcInfo, a routing model that determines the best route by finding the path of least resistance.

[Internet] A process by which a Web application assumes the identity of a particular user and thus gains all the privileges to which that user is entitled.

[programming] In programming an interface, to provide code for each of the methods of an interface (the interface is defined separately).

[data conversion] To bring data from one computer system or application into another. Importing often involves some form of data conversion.

[computing] Within the process space of a client application, a class contained in a DLL is in-process, as objects are loaded into the process space of the client EXE. A … Read more

[programming] An interface implemented by a class, on which a client can call members.

[network analysis] In ArcGIS Network Analyst, a network location used in closest facility analysis. Car accidents, crime scenes, and fires are examples of incidents.

[physics] Electromagnetic radiation that strikes a surface.

[standards] Acronym for International Committee for Information Technology Standards. An ANSI-accredited forum that creates and maintains information and communications technology standards through the participation and consensus of its industry members.

[statistics] One or a set of variables used to model or predict the dependent variable. For example, a prediction of annual purchases for a proposed store (the dependent variable) might … Read more

[network analysis] In networks, a flow direction that is unknown or undiscoverable. Indeterminate flow direction occurs when flow direction cannot be determined from the connectivity of the network, the locations … Read more

[computing] A data structure, usually an array, used to speed the search for records in a database or for spatial features in geographic datasets. In general, unique identifiers stored in … Read more

On a topographic map, a contour line that is thicker than the rest and usually labeled with the elevation that it represents. Depending on the contour interval, every fourth or … Read more

[cartography] A schematic map used as a reference for a collection of map sheets, outlining the total area covered along with the coverage extent of, and usually a name or … Read more

[organizational issues] An organization with specific GIS needs. Examples of industries include government, transportation, health care, homeland security, and public safety.

[ESRI software] A tabular database management system used by ArcInfo Workstation software to store and manipulate attributes of a GIS dataset in ArcInfo Workstation format. INFO databases are stored inside … Read more

[cognition] A geometric representation of relationships between elements in a data domain, in which relative position indicates the degree of similarity between elements. Information spaces are often based on geographic … Read more

[non-ESRI software] A commercial relational database management system (RDBMS) supported by ArcSDE.

[data capture] A device that detects infrared radiation and nverts it into an electrical signal that can be recorded on film or magnetic tape.

[government] The system of human-made physical structures, such as roads, bridges, canals, cables, wires, communications towers, hospitals, pipes, reservoirs, and sewers, that provide communication, transportation, public services, utilities, or all … Read more

[computing] In object-oriented programming, the acquisition of methods and properties by child classes or interfaces from their previously existing parent classes or interfaces. Inheritance is one of the defining characteristics … Read more

[modeling] Data that is entered into a computer, device, program, or process.

[ESRI software] In geocoding, a piece of information such as a customer address and location of an incident. Input event record types vary by application. They include customer addresses, location … Read more

[analysisgeoprocessing] In geoprocessing, data put into the system for processing, usually specified by a path in a dialog box, script, or at the command line.

[analysisgeoprocessing] In geoprocessing, tabular data put into the system for processing, usually specified by a path in a dialog box, script, or at the command line.

[map design] A small map set within a larger map. An inset map might show a detailed part of the map at a larger scale, or the extent of the … Read more

1 [computing] In object-oriented programming, a single object created based on the template or definition of the class to which it belongs. 2 [ESRI software] In ArcSDE, a single installation … Read more

[computing] In programming, the process of creating a single object based on the template or definition of the class to which it belongs.

[ESRI software] In the Survey Analyst for field measurements Survey Explorer, a field that allows the user to select the instrument setup or enter the name of a new instrument … Read more

[ESRI software] In geodatabases, a feature dataset that stores topologically associated feature classes. The topological editing tools in ArcMap can be used to maintain the topological associations of features in … Read more

[data transfer] A high degree of interconnection between two or more programs or datasets, in which they share a common schema, ontology, semantic approach, or method that allows information to … Read more

In the IHS (intensity, hue, saturation) color model, the relative brightness of a color.

[data conversion] A manual process for converting raster data into vector features that involves tracing raster cells.

[data sharing] A file format that allows the easy exchange of data between different software programs.

[remote sensing] A radar image that records interference patterns captured by two antennae a short distance apart.

[ESRI software] One of two weights that allow control of how labels are placed relative to polygon features in ArcMap. Higher feature weights prevent labels from being placed over features. … Read more

[modeling] Any data in a process that did not exist before the process existed and that will not be maintained after the process executes.

[coordinate systems] An imaginary line, generally following the meridian of longitude lying 180 degrees east and west of the Greenwich meridian, where the date changes. The time zone east of … Read more

[organizational issues] The process of creating software that can be adapted to the requirements of different languages and cultures without substantive changes to the source code.

The global network of computers that communicate through common protocols, such as TCP/IP.

[interoperability] The capability of components or systems to exchange data with other components or systems, or to perform in multiple environments. In GIS, interoperability is required for a GIS user … Read more

1 [mathematics] The estimation of surface values at unsampled points based on known surface values of surrounding points. Interpolation can be used to estimate elevation, rainfall, temperature, chemical dispersion, or … Read more

[map projections] A world projection that reduces distortion by dividing the projected area into gores, each with its own central meridian.

[analysisgeoprocessing] A geometric integration of spatial datasets that preserves features or portions of features that fall within areas common to all input datasets.

[data management] The point where two lines cross. In geocoding, most often a street crossing.

[data structures] Data classified on a linear calibrated scale, but not relative to a true zero point in time or space. Because there is no true zero point, relative comparisons … Read more

[Internet] A computer network, often using the same software and serving the same functions as those found on the Internet, that is restricted to users within an organization.

[spatial statistics use for geostatistics] In spatial statistics, the assumption that a set of data comes from a random process with a constant mean and a semivariogram that depends only … Read more

[statistics] One divided by distance, often raised to some power (1/D or 1/D2, for example), where D is a distance value. By inverting the distance among spatial features, and using … Read more

An interpolation technique that estimates cell values in a raster from a set of sample points that have been weighted so that the farther a sampled point is from the … Read more

Acronym for Internet protocol address. A unique number, such as 10.48.6.8, that identifies each computer on the Internet. IP addresses are similar to phone numbers, and allow data to travel … Read more

[cartography] A line on a map connecting points of equal difference from a normal value, usually a meteorological value such as average temperature.

1 [cartography] An isoline drawn according to values that can occur at points; an isometric line. 2 [cartography] A line connecting points of equal value on a map; an isoline.

[standards] Abbreviation for International Organization for Standardization. A federation of national standards institutes from 145 countries that works with international organizations, governments, industries, businesses, and consumer representatives to define and … Read more

A line on a weather map connecting places of equal barometric pressure.

1 [cartography] A line on a map connecting points of equal elapsed time; especially, travel time to or from a given location. 2 [cartography] A line on a map connecting … Read more

[cartography] A line on a map connecting points of equal rainfall.

[ESRI software] A setting in a database management system (DBMS) that defines how much an application process is isolated from other concurrently executing processes in a DBMS. It specifies the … Read more

[cartography] A line connecting points of equal value on a map. Isolines fall into two classes: those in which the values actually exist at points, such as temperature or elevation … Read more

[cartography] An isoline drawn according to known values, either sampled or derived, that can occur at points. Examples of sampled quantities that can occur at points are elevation above sea … Read more

[cartography] An isoline drawn according to known values that can only be recorded for areas, not points. Examples include population per square mile or the ratio of residential land to … Read more

A line on a map connecting points of equal temperature.

[analysisgeoprocessing] Having uniform spatial distribution of movement or properties, usually across a surface.

[spatial statistics use for geostatistics] A property of a natural process or data where spatial dependence (autocorrelation) changes only with the distance between two locationsdirection is unimportant.

1 [ESRI software] An element in the Catalog tree. Items include data sources, such as shapefiles and geodatabases, and nonspatial elements, such as folders. 2 [ESRI software] In coverages, a … Read more

[computing] A repetitive or recurring procedure.

[programming] All COM interfaces inherit from the IUnknown interface. The default implementation of IUnknown controls object lifetime and provides runtime type support.