GIS Dictionary

[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.