GIS Dictionary

[data models] A point, line, or polygon that is not part of a geometric network and is not an annotation feature, dimension feature, or custom object.

[ESRI software] In a geodatabase, a junction feature that corresponds to a single network element in the logical network.

[ESRI software] In a geodatabase, a junction feature that corresponds to a single network element in the logical network.

A kriging method in which the weights of the values do not sum to unity. Simple kriging uses the average of the entire dataset, which is less accurate than ordinary … Read more

An area defined by a generalized boundary drawn around the most distant set of customer points (a convex hull) that total to some value. The calculation may be unweighted (in … Read more

[ESRI software] The simplest form in which measurements from COGO sources or TPS (Total Positioning System) sources can be stored.

[data structures] A link or association between data sources that exist independently of each other.

[ESRI software] In ArcGIS Tracking Analyst, an event that contains all necessary information in one temporal data message (for real-time data) or record (for fixed-time data).

[map design] A type of cartographic generalization in which the important characteristics of features are determined and unwanted detail is eliminated to retain clarity on a map whose scale has … Read more

[cadastral and land records] A means of defining multiple units of land in a single survey document in such a way that all their boundaries have equal legal status. A … Read more

[data quality] A level of coordinate exactness based on the number of significant digits that can be stored for each coordinate. Single precision numbers store up to seven significant digits … Read more

[ESRI software] One of two types of setup pages in the Survey Analyst Survey Explorer. The single setup page is used for computations that process single instrument setups.

[software] In software licensing, a software product that can be used on only one machine.

[database structures] A geodatabase that can handle a single editor and multiple readers.

[programming] A class for which there can only be one instance in any process.

1 [analysisgeoprocessing] The location or group of locations used as the endpoint for distance analysis. 2 [network analysis] A junction feature that pulls flow toward itself through the edges of … Read more

The process of evaluating demographic data surrounding potential locations for a business, based on a user-defined trade area or areas.

[ESRI software] A downloadable application that users can customize and use on their site.

[data models] In ArcMap, a shape that represents a feature’s geometry. Every existing feature on a map has this alternate form, a sketch, that allows visualization of that feature’s composition, … Read more

[ESRI software] In ArcMap editing, an angle or length limitation that can be placed on segments created using the Sketch tool.

[ESRI software] In ArcMap, an editing operation that is performed on an existing sketch. Examples are Insert Vertex, Delete Vertex, Flip, Trim, Delete Sketch, Finish Sketch, and Finish Part. All … Read more

[ESRI software] Prior to ArcGIS 10, a tool that adds points, vertices, or segments to create an edit sketch. Sketch points can be defined by heads-up digitizing, snapping, or manually … Read more

[data models] A small, narrow, polygon feature that appears along the borders of polygons following the overlay of two or more geographic datasets. Sliver polygons may indicate topology problems with … Read more

[data editing] The act of deleting unwanted sliver polygons.

[Euclidean geometry] The incline, or steepness, of a surface. Slope can be measured in degrees from horizontal (090), or percent slope (which is the rise divided by the run, multiplied … Read more

[geodesy] The circle made when a flat plane intersects a sphere anywhere but through its center. Parallels of latitude other than the equator are small circles.

[cartography] Generally, a map scale that shows a relatively large area on the ground with a low level of detail.

[programming] A Visual C++ class implementation that encapsulates an interface pointer, providing operators and functions that can make working with the underlying type easier and less error prone.

[digital image processing] In image processing, reducing or removing small variations in an image to reveal the global pattern or trend, either through interpolation or by passing a filter over … Read more

[ESRI software] An ArcGIS geoprocessing option that snaps, or aligns, all layers to the cell registration of a specified raster. All layers will share the lower left corner and cell … Read more

[ESRI software] An option in the Environment Setting dialog box that ensures the cell alignment of the extent will match accurately with an existing raster. This is done by snapping … Read more

[data editing] The process of moving a feature to match or coincide exactly with another point or feature’s coordinates when your pointer is within a specified distance (tolerance). Commonly used … Read more

[ESRI software] Settings in ArcGIS that define the conditions in which snapping will occur. These settings include snapping tolerance, snapping properties, and snapping priority. When you are editing, there are … Read more

[ESRI software] In classic snapping, the order in which snapping will occur by layer during an ArcGIS editing session, set from the Snapping Environment window.

[ESRI software] In classic snapping, a combination of a shape to snap to and a method for determining what part of the shape will be snapped to. Snapping properties can … Read more

1 [data editing] A specified distance within which points or features within are moved to match or coincide exactly with each others’ coordinates. 2 [ESRI software] In an ArcGIS editing … Read more

[ESRI software] In ArcGIS, a user-assistance component that displays an on-screen description of the layer name or target being snapped to when the mouse pointer is paused over it. SnapTips … Read more

[computing] An XML-based protocol developed by Microsoft, SAP, and IBM for exchanging information between peers in a decentralized, distributed environment. SOAP allows programs on different computers to communicate independently of … Read more

[software] Acronym for server object container. A process in which one or more services is running, or the machine hosting this process. SOC processes are started and shut down by … Read more

[software] A ready-to-use application geared toward a specific audience or industry.

[network analysis] A function that performs network analysis based on a set of network data.

[software] Acronym for server object manager. A Windows service that manages a set of server objects that are distributed across one or more server object container machines, or the machine … Read more

[remote sensing] Acronym for sound navigation and ranging. A system or device that measures the time lapse between emitting a sound and receiving a returned echo to determine the location, … Read more

[computing] A method of phonetic spelling used for searches and address matching. Soundex uses an algorithm to represent letters and numbers with similar phonetic equivalents to facilitate searching.

1 [analysisgeoprocessing] The location or group of locations used as the starting point for distance analysis. 2 [network analysis] A junction feature that pushes flow away from itself through the … Read more

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

[coordinate systems] A three-dimensional, rectangular, Cartesian coordinate system that has not been adjusted for the earth’s curvature. In a space coordinate system, the x- and y-axes lie in a plane … Read more

[data capture] Vector data composed of simple lines with no topology and usually no attributes. Spaghetti lines may cross, but no intersections are created at those crossings.

[data capture] Digitizing that does not identify intersections as it records lines.

[data models] Related to or existing within space.

[ESRI software] An ArcMap editing function that allows transformation, rubber sheeting, and edgematching of data, as well as attribute transfer.

[spatial analysis] The process of examining the locations, attributes, and relationships of features in spatial data through overlay and other analytical techniques in order to address a question or gain … Read more

[spatial statistics use for geostatistics] A measure of the degree to which a set of spatial features and their associated data values tend to be clustered together in space (positive … Read more

[ESRI software] In ArcMap, a shortcut created by the user that identifies a particular geographic location to be saved for later reference.

The mental processes involved in gaining and using knowledge and beliefs about spatial environments. Spatial cognition includes issues of perception, memory, language, learning, and problem solving, and is an object … Read more

1 [data structures] Information about the locations and shapes of geographic features and the relationships between them, usually stored as coordinates and topology. 2 [data models] Any data that can … Read more

[database structures] A structured collection of spatial data and its related attribute data, organized for efficient storage and retrieval.

1 [standards] For a spatial dataset in ArcGIS 9.1 and previous versions, the defined precision and allowable range for x- and y-coordinates and for m- and z-values, if present. 2 … Read more

[ESRI software] In ArcGIS Spatial Analyst, an operation that performs spatial analysis. All Spatial Analyst tools in the Spatial Analyst toolbox, and operations on the ArcGIS Spatial Analyst toolbar, are … Read more

[data models] A two-dimensional grid system that spans a feature class. It is used to quickly locate features in a feature class that might match the criteria of a spatial … Read more

[ESRI software] In a geodatabase, a mechanism for optimizing access to data based on the spatial column of the business table. In most geodatabases, a system of grids is used … Read more

[spatial analysis] A type of table join operation in which fields from one layer’s attribute table are appended to another layer’s attribute table based on the relative locations of the … Read more

[modeling] A methodology or set of analytical procedures used to derive information about spatial relationships between geographic phenomena.

[analysisgeoprocessing] The process of superimposing layers of geographic data that cover the same area to study the relationships between them.

[analysisgeoprocessing] A type of analysis in which data is extracted from one layer (such as block groups) to an overlay layer (such as a trade area).

[spatial analysis] A statement or logical expression that selects geographic features based on location or spatial relationship. For example, a spatial query might find which points are contained within a … Read more

[ESRI software] In ArcGIS 9.2 or later, the coordinate system, tolerance, and resolution used to store a spatial dataset.

[statistics] The field of study concerning statistical methods that use space and spatial relationships (such as distance, area, volume, length, height, orientation, centrality and/or other spatial characteristics of data) directly … Read more

[spatial statistics use for geostatistics] A file that quantifies spatial relationships among a set of features. Typical examples of such relationships are inverse distance, contiguity, travel time, and fixed distance.

The transformation of complex, multivariate, nonspatial data into a spatial representation located in an information space. The relative positioning of data elements within the spatial representation shows relationships between them. … Read more

[ESRI software] In ArcGIS Network Analyst, an object used in vehicle routing problem (VRP) analysis. A specialty is used to represent a specific capability that may be required by certain … Read more

[satellite imaging] The range of wavelengths that an imaging system can detect.

[physics] The pattern of electromagnetic radiation that identifies a chemical or compound. Materials can be distinguished from one another by examining which portions of the spectrum they reflect and absorb.

[physics] A photometer that measures the intensity of electromagnetic radiation as a function of its frequency. Spectrophotometers are usually used for measuring the visible portion of the spectrum.

[physics] The scientific study of how different chemicals and other substances absorb and reflect different parts of the electromagnetic spectrum.

[geolocating] In geocoding, the degree to which the spelling variation of a street name is allowed during a search for likely match candidates. The lower the value, the more likely … Read more

[Euclidean geometry] A three-dimensional shape whose center is equidistant from every point on its surface, made by revolving a circle around its diameter.

[coordinate systems] A reference system using positions of latitude and longitude to define the locations of points on the surface of a sphere or spheroid.

1 [Euclidean geometry] A three-dimensional shape obtained by rotating an ellipse about its minor axis, resulting in an oblate spheroid, or about its major axis, resulting in a prolate spheroid. … Read more

1 [statistics] An anomalous data point that protrudes above or below an interpolated surface. 2 [data capture] An overshoot line created erroneously by a scanner and its rasterizing software.

In mathematics, a piecewise polynomial function used to approximate a smooth curve in a line or surface.

[spatial statistics use for geostatistics] An interpolation method in which cell values are estimated using a mathematical function that minimizes overall surface curvature, resulting in a smooth surface that passes … Read more

[ESRI software] A user-designated character that divides long labels into two or more lines during the labeling process. There can be more than one split character.

[ESRI software] All attribute domains in geodatabases have a split policy associated with them. When a feature is split into two new features in ArcMap, the split policies dictate what … Read more

[satellite imaging] Acronym for Satellite Pour lObservation de la Terre. Earth observation satellites developed by Centre National d’Etudes Spatiales (CNES), the space agency of France. The SPOT satellites gather high-resolution … Read more

[surveying] An elevation measurement taken at a single location.

[programming] Acronym for Structured Query Language. A syntax for retrieving and manipulating data from a relational database. SQL has become an industry standard query language in most relational database management … Read more

[Internet] Acronym for Secure Sockets Layer. An encryption protocol for the secure transfer of private information over the Internet.

[programming] Acronym for single threaded apartment. An apartment that has only a single thread. User interface code is usually placed in an STA.

[cartography] In cartography, any material such as a Mylar sheet or film that is more durable than paper and less likely to shrink or stretch.

1 [computing] In computing, a data storage structure that operates on last in, first out (LIFO) protocol. As with a stack of dishes, the item placed on top of the … Read more

[software] An application that runs by itself, not within an ArcGIS application.

[ESRI software] Annotation that is stored in the geodatabase, consisting of geographically placed text strings that are not associated with features in the geodatabase.

A statistical measure of the spread of values from their mean, calculated as the square root of the sum of the squared deviations from the mean value, divided by the … Read more

A data classification method that finds the mean value, then places class breaks above and below the mean at intervals of either .25, .5, or 1 standard deviation until all … Read more

[spatial statistics use for geostatistics] A measure of the compactness of a spatial distribution of features around its mean center. Standard distance (or standard distance deviation) is usually represented as … Read more

[standards] The federal U.S. standard for classifying establishments by their primary type of business activity. Standard Industrial Classification codes (SIC codes) are used as an identification system in business directories, … Read more

[map projections] A line on a sphere or spheroid that has no length compression or expansion after being projected; usually a standard parallel or central meridian.

[map projections] The line of latitude in a conic or cylindrical projection in normal aspect where the projection surface touches the globe. A tangent conic or cylindrical projection has one … Read more

[cartography] A type of diagram that consists essentially of a central point from which lines radiate outward. The central point usually represents a geographic location while the length of each … Read more