GIS Dictionary

[navigation] A navigation method of last resort that uses the most recently recorded position of a ship or aircraft, along with its speed and drift, to calculate a new position.

[computing] To test for, detect, and correct errors in a computer program or component.

[map projections] Values of latitude and longitude expressed in decimal format rather than in degrees, minutes, and seconds.

[computing] A computer program that includes data presentation and modeling tools that help people understand problems and find solutions.

1 [coordinate systems] In a spherical coordinate system, the angle between the equatorial plane and a line to a point somewhere on the sphere. 2 [coordinate systems] The arc between … Read more

[computing] An application that uses the GIS server to maintain application state by changing the state of a server object or its related objects. Deeply stateful applications require nonpooled server … Read more

[ESRI software] In Survey Analyst – Cadastral Editor, the most up-to-date version of the cadastral fabric in the database that corresponds to the default version in the database. The default … Read more

[Internet] When a COM object is created, the interface that is returned automatically if no other interface is specified. Most ArcObjects classes specify IUnknown as the default interface.

[network analysis] In geometric networks, the user-established junction type that automatically connects two edges in the absence of a current user choice. An edge may also have a default end … Read more

[ESRI software] A study area with a defined boundary, such as a city.

[ESRI software] In ArcMap, a request that examines feature or tabular attributes based on user-selected criteria and displays only those features or records that satisfy the criteria.

[data editing] The creation of a segment at an angle relative to an existing segment.

[geodesy] A unit of angular measure represented by the symbol . The earth is divided into 360 degrees of longitude and 180 degrees of latitude.

The unit of measure for describing latitude and longitude. A degree is 1/360th of a circle. A degree is further divided into 60 minutes, and a minute is divided into … Read more

[3D analysis] The components of Delaunay triangulation. Delaunay triangles cannot exist alone; they must exist as part of a set or collection that is typically referred to as a triangulated … Read more

[3D analysis] A technique for creating a mesh of contiguous, nonoverlapping triangles from a dataset of points. Each triangle’s circumscribing circle contains no points from the dataset in its interior. … Read more

[database structures] The geodatabase system table, created when a feature class or table is registered as versioned, that maintains information on all rows that have been deleted or updated.

[computing] A character, such as a space or comma, that separates words or values.

[data editing] A file that contains data edits that can be exchanged between geodatabases or between geodatabases and other data stores. The edits can come from a checkout geodatabase, modified … Read more

[database structures] One of two geodatabase system tablesthe adds and deletes tablescreated for a feature class or table when it is registered as versioned. These tables record changes made to … Read more

[data models] Acronym for digital elevation model. The representation of continuous elevation values over a topographic surface by a regular array of z-values, referenced to a common vertical datum. DEMs … Read more

[geography] The statistical characteristics (such as age, birth rate, and income) of a human population.

[geography] The statistical study of human populations, especially their locations, distribution, economic statistics, and vital statistics.

[data editing] To add vertices to a line at specified distances without altering the line’s shape.

[graphics map display] An instrument for measuring the opacity of translucent materials such as photographic negatives and optical filters.

1 [Euclidean geometry] In spatial measurements, the quantity per unit area or length. 2 [physics] In a substance such as a gas, solid, or liquid, a measurement of the ratio … Read more

[remote sensing] A technique normally applied to a single-band monochrome image for highlighting areas that appear to be uniform in tone, but are not. Grayscale values (0-255) are converted into … Read more

[statistics] The variable representing the process being predicted or modeled, such as crime, foreclosure, or rainfall. The dependent variable is a function of the independent variables. Regression can be used … Read more

[computing] The installation of a component or application on a target machine.

[ESRI software] In ArcGIS Network Analyst, a network location used to represent a starting, stopping, or renewal location for routes in vehicle routing problem (VRP) analysis. Users can specify multiple … Read more

[ESRI software] In ArcGIS Network Analyst, an object used to represent a single visit to a specific depot in vehicle routing problem (VRP) analysis. A depot visit may occur at … Read more

[symbology] A line on a map connecting points of equal depth below a hydrographic datum.

In ModelBuilder, data created by running a geoprocessing operation on existing data. Derived data from one process can serve as input data for another process.

The point at which a satellite traveling north to south crosses the equator.

[network analysis] A type of attribute for network elements that cannot be apportioned. The value of a descriptor stays the same through the length of an edge element in a … Read more

[data analysis] A type of market analysis that draws lines from a set of geocoded points (usually customers) to a single, central point (usually a store). Desire lines can be … Read more

[data management] Mapping software that is installed onto and runs on a personal computer and allows users to display, query, update, and analyze data about geographic locations and the information … Read more

[computing] The secondary object in a relationship class, such as a table containing attributes associated with features in a related table.

[ESRI software] In ArcView 3.x, one of the two tables involved in a join operation. The destination table must be the active table; the attributes of the source (inactive) table … Read more

[ESRI software] One of two types of pages in the Survey Analyst Survey Explorer. The Detail page displays a detailed view of individual survey objects.

[network analysis] A conclusively definitive line or course in which something is issuing or moving in a stream. For an edge feature, this occurs when the flow direction can be … Read more

[spatial statistics use for geostatistics] In spatial modeling, a type of model or a part of a model in which the outcome is completely and exactly known based on known … Read more

[statistics] The process of removing the trend from a spatial model by subtracting the trend surface (usually polynomial functions of the spatial x- and y-coordinates) from the original data values. … Read more

[map projections] A geometric shape such as a cone, cylinder, or plane that can be flattened without being distorted. Many map projections are classified in terms of these shapes.

[ESRI software] Products that can be used on one machine, similar to single use products. Each developer product requires a unique registration number used to generate the authorization file. The … Read more

[ESRI software] A sample contained in the ArcGIS Developer Help system.

[programming] A software product used to write, compile, and debug components or applications.

[ESRI software] Represents a surface that can be drawn to, for example, a screen, bitmap, or printer. In ArcGIS, the Display abstract class is used to abstract a device context.

[graphics computing] The coordinates shown on a digitizer or display, as opposed to those of a recognized datum or coordinate system.