GIS Dictionary

[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.

The difference in elevation between adjacent contour lines.

[cartography] A line on a map that connects points of equal elevation based on a vertical datum, usually sea level.

[data capture] Assigning elevation values to contour lines.

[remote sensing] In remote sensing and photogrammetry, the ratio between the energy emitted or reflected by an object and that emitted or reflected by its immediate surroundings.

[graphics computing] The ratio between the maximum and minimum brightness values in an image.

[graphics computing] Increasing the contrast in an image by expanding its grayscale range to the range of the display device.

[computing] A basic element of a software application’s GUI. Examples of controls include menus, buttons, tools, check boxes, slider bars, text input boxes, and combo boxes.

1 [surveying] An accurately surveyed coordinate location for a physical feature that can be identified on the ground. Control points are used in least-squares adjustments as the basis for improving … Read more

[spatial statistics use for geostatistics] In statistical testing, a set of assumptions that will be accepted by test data if the null hypothesis is rejected. In surveying, the alternative hypothesis … Read more

[cartography] The angle between a vertical line (grid north) and true north on a map.

[data conversion] The process of changing input data from one representation or format to another, such as from raster to vector, or from one file format to another, such as … Read more

[mathematics] The smallest convex polygon that encloses a group of objects, such as points. In ArcGIS, TIN boundaries are convex hulls by default.

[mathematics] A polygon in which a straight line drawn between any two points inside the polygon is completely contained within the polygon. Visually, the boundary of a convex polygon is … Read more

[ESRI software] In Survey Analyst, a process of computing a sequence of survey point locations starting from an initial known point. Each new survey point is defined by a traverse … Read more

A reference framework consisting of a set of points, lines, and/or surfaces, and a set of rules, used to define the positions of points in space in either two or … Read more

The process of converting the coordinates in a map or image from one coordinate system to another, typically through rotation and scaling.

[astronomy] The official timekeeping system of the world’s nations since 1972. It refers local time throughout the world to time at the prime meridian, and is based on atomic clocks, … Read more

[coordinate systems] A set of values represented by the letters x, y, and optionally z or m (measure), that define a position within a spatial reference. Coordinates are used to … Read more

[statistics] An association between data or variables that change or occur together. For example, a positive correlation exists between housing costs and distance from the beach; generally, the closer a … Read more

[data models] A buffer drawn around a line.

[spatial analysis] A form of spatial analysis usually applied to environmental and land-use data in order to find the best locations for building roads, pipelines, and other linear transportation features.

1 [data analysis] A function of time, distance, or any other factor that incurs difficulty or an outlay of resources. 2 [network analysis] In ArcGIS Network Analyst, an attribute of … Read more

[spatial analysis] A raster dataset that identifies the cost of traveling through each cell in the raster. A cost raster can be used to calculate the cumulative cost of traveling … Read more

[ESRI software] The calculation of the least cumulative cost from each cell to specified source locations over a cost raster.

[ESRI software] An ArcGIS Spatial Analyst function that identifies the nearest source from each cell in a cost-weighted distance grid. Each cell is assigned to its nearest source cell, in … Read more

[ESRI software] An ArcGIS Spatial Analyst function that provides a road map from the cost weighted distance grid, identifying the route to take from any cell, along the least-cost path, … Read more

[ESRI software] An ArcGIS Spatial Analyst function that uses a cost grid to assign a valuethe least accumulative cost of getting back to the sourceto each cell of an output … Read more

[software] Acronym for commercial off-the-shelf. Commercially available software or systems that are ready to use and which do not require significant customization.

[federal government] The primary legal subdivision of all U.S. states except Alaska and Louisiana. The U.S. Census Bureau uses counties or equivalent entities (boroughs in Alaska, parishes in Louisiana, the … Read more

[federal government] A statistical division of a county recognized by the U.S. Census Bureau for data presentation. County subdivisions can include census county divisions, census subareas, minor civil divisions, and … Read more

[statistics] A statistical measure of the linear relationship between two variables. Covariance measures the degree to which two variables move together relative to their individual mean returns.

[ESRI software] A data model for storing geographic features. A coverage stores a set of thematically associated data considered to be a unit. It usually represents a single layer, such … Read more

In ArcInfo, a classification describing the format of geographic features and supporting data in a coverage. Feature classes include point, arc, node, route, route system, section, polygon, and region. One … Read more

[coordinate systems] The units of the coordinate system in which a coverage is stored (for example, feet, meters, inches).

[data editing] In ArcGIS, a part of the topology validation process in which vertices are created at the intersection of feature edges.

1 [surveying] A special-case, least-squares-based method for adjusting the closure error in a traverse. The Crandall rule is most frequently used in a closed traverse that represents a parcel from … Read more

[ESRI software] In Survey Analyst for field measurements, an attribute of the computation that records the date of origin.

[ESRI software] In Survey Analyst for field measurements, an attribute of the computation that records the date of origin.

[ESRI software] The time it takes to initialize an instance of a server object when server objects are created in the GIS server either as a result of the server … Read more

[spatial statistics use for geostatistics] The specific cutoff point that determines acceptance or rejection of a hypothesis. Critical values are determined by the choice of a level of significance ().

[printing] Marks that indicate the edge of the page of a finished, printed map. Cropmarks are used as a reference for trimming excess paper after printing.

[spatial statistics use for geostatistics] Statistical correlation between spatial random variables of different types, attributes, names, and so on, where the correlation depends on the distance or direction that separates … Read more

[statistics] The statistical tendency of variables of different types, attributes, names, and so on, to vary in ways that are related to each other. Positive cross covariance occurs when both … Read more

1 [data analysis] In a GIS, comparing attributes in different coverages or map layers according to location. 2 [statistics] A method for showing the relationship between two or more data … Read more

[statistics] A procedure for testing the quality of a predicted data distribution. In cross validation, a piece of data whose value is known independently is removed from the dataset and … Read more

[spatial statistics use for geostatistics] A function of the distance and direction separating two locations, used to quantify cross correlation. The cross variogram is defined as the variance of the … Read more

[ESRI software] A database containing tables with information defining the mapping between a data source schema and an output geodatabase schema. Cross-reference databases are used by the PLTS data loader … Read more

[ESRI software] A technique for indexing features that cross tile boundaries in a map library by storing them as one or more features in each tile, instead of storing them … Read more

[non-ESRI software] Acronym for Cascading Style Sheets. A standard for defining the layout or presentation of an HTML or XML document. Style information includes font size, background color, text alignment, … Read more

[mathematics] A technique for resampling raster data in which the average of the nearest 16 cells is used to calculate the new cell value.

[ESRI software] In ArcScene and ArcGlobe, to selectively choose not to draw one side of an areal feature.

[cartography] A human-made feature represented on a map, such as a building, road, tower, or bridge.

[cognition] The field of geography concerning the spatial distribution and patterns created by human cultures and their effects on the earth.

[network analysis] In network analysis, a network location property that models a path for approaching a stop from a specific side based on edge direction. For example, a school bus … Read more

[ESRI software] In Survey Analyst – Cadastral Editor, the most up-to-date legal state of the cadastral fabric.

[ESRI software] In Survey Analyst for field measurements, the single coordinate for a survey point that is the best representation for its location within each project. A current coordinate is … Read more

[ESRI software] A user-specified path to a container for file-based geographic data, set in the Environment Settings dialog box. Data from the current workspace can be accessed from any tool … Read more

[data editing] Converting short connected straight lines into smooth curves to represent features such as rivers, shorelines, and contour lines. The curves that result pass through or close to the … Read more

[computing] A set of methods, functions or operations associated with a database object that has been specifically created or overridden by a programmer.

[computing] In geodatabases, a feature with specialized behavior instantiated in a class by a programmer.

[computing] A modification to or enhancement of standard software functionality to meet a specific user’s needs.

[ESRI software] A layer created in ArcMap using the ArcGIS Image Server extension. Custom group layers display the contents of an image service definition, including the footprint, boundary, seamline and … Read more

[computing] An object with custom behavior provided by a developer.

[ESRI software] In geoprocessing, a tool created by a user and added to a toolset and/or toolbox. Custom tools may only be added to custom toolsets and/or toolboxes.

[ESRI software] In geoprocessing, a subset of a toolbox created by a user to hold custom tools or a group of frequently used tools.

[business] A type of market analysis that focuses on data about customers, rather than about a store or stores. An example is desire line analysis.

[business] A process that establishes common demographic characteristics for a set of customers within a geographic area.

[business] A type of market analysis that locates regions with appropriate demographic characteristics for targeting new customers.

[ESRI software] An ArcGIS Spatial Analyst and 3D Analyst function that summarizes areas and volumes of change between two surfaces.

1 [data models] A set of lines forming a closed polygon. 2 [network analysis] In network analysis, a path or tour beginning and ending at the same location. 3 [physics] … Read more

A projection that transforms points from a spheroid or sphere onto a tangent or secant cylinder. The cylinder is then sliced from top to bottom and flattened into a plane.