GIS Dictionary

[ESRI software] In Survey Analyst for field measurements, one of two possibilities for performing a constrained adjustment. In the weighted constrained adjustment, the reference point coordinates are treated as observed … Read more

[spatial statistics use for geostatistics] The geographic center of a set of points as adjusted for the influence of a value associated with each point. For example, while the mean … Read more

[spatial statistics use for geostatistics] The value of a point’s attribute computed by averaging the values of its surrounding points, taking into account their importance or their distance from the … Read more

[data analysis] A technique for combining multiple rasters by applying a common measurement scale of values to each raster, weighting each according to its importance, and adding them together to … Read more

[geodesy] Acronym for World Geodetic System 1972. A geocentric datum and coordinate system designed by the U.S. Department of Defense, no longer in use.

[geodesy] Acronym for World Geodetic System 1984. The most widely used geocentric datum and geographic coordinate system today, designed by the U.S. Department of Defense to replace WGS72. GPS measurements … Read more

[programming] A SQL clause that specifies a selection criterion that allows filtering of a query result set.

[ESRI software] An interactive graphic component of a user interface (such as a button, scroll bar, or menu bar), its controlling program, or the combination of both the component and … Read more

[meteorology] A diagram showing, for a given place and time period, how much of the time the wind blows from each direction. Wind roses have many variations, but in the … Read more

[graphics map display] The process of limiting the viewable extent of a map or data by panning and zooming.

[graphics computing] A three-dimensional picture of an object, composed entirely of lines (wires). The lines represent the edges or surface contours, including those that would otherwise be hidden by a … Read more

[Internet] A ready-to-use Web application for a wireless client such as a handheld device, PDA, or cellular phone, designed for a specific purpose such as maps and routing for travel … Read more

[software] An interactive user interface that helps a software user complete a task one step at a time. Wizards are often implemented as a sequence of dialog boxes that the … Read more

[organizational issues] One specific task that proceeds through each stage of an organization’s workflow process, including design, acceptance, and construction in the field.

1 [organizational issues] An organization’s established processes for design, construction, and maintenance of programs, products, and business objectives. 2 [organizational issues] A set of tasks carried out in a certain … Read more

[ESRI software] A Microsoft SQL Server Express database that uses ArcSDE technology to store, query, and modify spatial data. Workgroup geodatabases accept up to 10 non-Web client connections and unlimited … Read more

[computing] A directory that indicates the appropriate location on disk to place results from analysis.

1 [ESRI software] A container for geographic data. A workspace can be a folder that contains shapefiles, a geodatabase, a feature dataset, or an ArcInfo workspace. Other multidimensional data formats … Read more

[hardware] A computer that has better graphics capabilities and more processing power than most personal computers, and is able to carry out several tasks at once. Workstations usually share data … Read more

[data storage] A text file containing information about where an image should be displayed in real-world coordinates. When an image has a properly configured world file, GIS software can use … Read more

[Internet] A worldwide, decentralized, public information space for sharing documents and conducting business on the Internet. Components of the World Wide Web include information in the form of HTML documents; … Read more

[Internet] Acronym for Web Service Description Language. An XML format for describing the methods, types, and connection point of a SOAP Web service.

[computing] In ArcGIS desktop, this term refers to the editing tools providing visual feedback of the desired end result of an editing operation while the process is still underway. For … Read more

[coordinate systems] A pair of values that represents the distance from an origin (0,0) along two axes, a horizontal axis (x), and a vertical axis (y). On a map, x,y … Read more

[mathematics] A simple coordinate pair that describes the location of a feature, such as a set of latitude and longitude degrees.

[coordinate systems] In a planar coordinate system, three coordinates that locate a point by its distance from an origin (0,0,0) where three orthogonal axes cross. Usually, the x-coordinate is measured … Read more

[coordinate systems] In a planar coordinate system, the horizontal line that runs right and left (east and west of) the origin (0,0).

[programming] XML for location-based services.

[programming] Acronym for XML Metadata Interchange. A standard that specifies how to store a UML model in an XML file.

[programming] Acronym for Extensible Markup Language. Developed by the W3C, a standardized general purpose markup language for designing text formats that facilitates the interchange of data between computer applications. XML … Read more

[programming] In ArcGIS, an export file containing the features or records from an individual geodatabase feature class or table. Data in the file is encoded in XML and can be … Read more

[programming] In ArcGIS, an export file containing one or more geodatabase feature datasets, feature classes, and tables. It can include schema and data or just the schema. Schema and data … Read more

[programming] A language used to find specific parts of an XML document and compute values from the document’s content.

[programming] Acronym for Extensible Style Language. A set of standards for defining XML document presentation and transformation. An XSL style sheet may contain information about how to display tagged content … Read more

[programming] Acronym for Extensible Style Language Transformations. A language for transforming the tagged content in an XML document into an output document with another format. An XSL style sheet contains … Read more

1 [coordinate systems] In a planar coordinate system, the vertical line that runs above and below (north and south of) the origin (0,0). Numbers north of the origin are positive, … Read more

[coordinate systems] In a spherical coordinate system, the vertical line that runs parallel to the earth’s rotation, passing through 90 degrees north latitude, and perpendicular to the equatorial plane, where … Read more

The value for a given surface location that represents an attribute other than position. In an elevation or terrain model, the z-value represents elevation; in other kinds of surface models, … Read more

[coordinate systems] A conversion factor used to adjust vertical and horizontal measurements into the same unit of measure. Specifically, the number of vertical units (z-units) in each horizontal unit. For … Read more

[statistics] A statistical measure of the spread of values from their mean, expressed in standard deviation units, where the z-score of the mean value is zero and the standard deviation … Read more

[coordinate systems] In raster-to-TIN conversion, the maximum allowed difference between the z-value of the input raster cell and the z-value of the output TIN at the location corresponding to the … Read more

[coordinate systems] The value for a given surface location that represents an attribute other than position. In an elevation or terrain model, the z-value represents elevation; in other kinds of … Read more

[astronomy] In astronomy, the point on the celestial sphere directly above an observer. Both the zenith and nadir lie on the observer’s meridian; the zenith lies 180 degrees from the … Read more

[ESRI software] In Survey Analyst for field measurements, a vertical angle that is formed by the intersection of two lines in a vertical plane. Zenith angles are observed on the … Read more

[linear referencing] In linear referencing, a line event whose from-measure is equal to its to-measure. A zero length line even may occur, for example, along routes, when a polygon touches … Read more

[federal government] Acronym for zone improvement plan code. A five-digit code, developed by the U.S. Postal Service, that identifies the geographic delivery area served by an individual post office or … Read more

[federal government] An enhanced ZIP Code that consists of the five-digit ZIP Code plus four additional digits that identify a specific geographic segment within the five-digit delivery area, such as … Read more

[spatial analysis] The creation of an output raster in which the desired function is computed on the cell values from the input value raster that intersect or fall within each … Read more

[ESRI software] In ArcGIS Spatial Analyst, the calculation of a statistic for each zone of a zone dataset based on values from another dataset, a value raster. A single output … Read more

1 [analysisgeoprocessing] All cells in a raster with the same value, regardless of whether or not they are contiguous. 2 [geocoding] Additional information about a location or address, used to … Read more

The area in a TIN layer for which values (elevation, slope, and aspect) are calculated. When a TIN layer is clipped to a smaller size to create a more focused … Read more

[local government] The application of local government regulations that permit certain land uses within geographic areas under the governments jurisdiction. Zoning regulations typically set a broad category of land use … Read more

[software] To display a larger or smaller region of an on-screen map or image.