GIS Dictionary

[ESRI software] A registration or geographic control point for a coverage representing a known location on the earth’s surface. Tics allow all coverage features to be recorded in a common … Read more

1 [symbology] Graphics that mark divisions of measurement on a scale bar. 2 [graphics map display] Short, regularly spaced lines along the edge of an image or neatline that indicate … Read more

[geodesy] A vertical datum in which zero height is defined by a particular tidal surface, often mean sea level. Examples of tidal surfaces include mean sea level, mean low water … Read more

[surveying] A point whose location is determined by a tie survey. [photogrammetry] A point in a digital image or aerial photograph that represents the same location in an adjacent image … Read more

[surveying] A survey that uses a point of known location on the ground to determine the location of a second point.

[geocoding] In geocoding, two or more records that yield the same score when matching an address.

[database structures] Acronym for Topologically Integrated Geographic Encoding and Referencing. The nationwide digital database developed for the 1990 census, succeeding the DIME format. TIGER files contain street address ranges, census … Read more

A digital database of geographic features, covering the entire United States and its territories, that provides a topological description of the geographic structure of these areas. The files are a … Read more

A high or complex degree of interconnections between the components within a program or between programs, that requires substantial overlap between methods, ontologies, class definitions, and so on.

[data structures] An internal subsetting of a spatial dataset (commonly raster) into a manageable rectangular set, or rows and columns of pixels, typically used to process or analyze a large … Read more

[ESRI software] One of two methods for displaying temporal data in ArcGIS Tracking Analyst: real-time mode or playback mode. Time modes are determined by the use of the Tracking Analyst … Read more

[network analysis] In networks, the time during which a stop can be visited. For example, on a bus route, each stop may have a time window of 15 minutes. If … Read more

[ESRI software] In ArcGIS Network Analyst, a time window violation occurs when a route arrives at a network location after its associated time window has closed.

Acronym for triangulated irregular network. A vector data structure that partitions geographic space into contiguous, nonoverlapping triangles. The vertices of each triangle are sample data points with x-, y-, and … Read more

[data structures] A dataset containing a triangulated irregular network (TIN). The TIN dataset includes topological relationships between points and neighboring triangles.

[ESRI software] A layer that references a set of TIN data. TIN data contains a triangulated irregular network (TIN) and includes topological relationships between points and neighboring triangles.

One of four types of edges that may be found in a TIN: regular lines, hard breaklines, soft breaklines, and outside lines. Regular lines define the TIN’s basic structure, connecting … Read more

[map projections] A graphical representation of the spatial distortion at a particular map location. The indicatrix is the figure that results when a circle on the earth’s surface is plotted … Read more