GIS Glossary

Definitions of common GIS terms

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Annotation - In ArcGIS, text or graphics that can be individually selected, positioned, and modified. Annotation may be manually entered or generated from labels. Annotation can be stored as features in a geodatabase or as map annotation in a data frame.

ArcCatalog - One of the 3 main components that make up ArcGIS. It allows users to browse, manage and document their geographic data. Also see ArcMap and ArcToolbox (GIS Centre, Dalhousie University)

ArcEditor - The midlevel of licensing in the ArcGIS Desktop product line. It contains all of the tools as ArcView plus more. In appearance it looks the same as ArcView only there are more tools available.(GIS Centre, Dalhousie University) Also see ArcView and ArcInfo. Click for a detailed comparison between the different licensing levels. A more general comparison of the functionality.

ArcGIS - An integrated collection of GIS software products that provides a standards-based platform for spatial analysis, data management, and mapping. ArcGIS is scalable and can be integrated with other enterprise systems such as work order management, business intelligence, and executive dashboards. (ESRI website - March 2010)

ArcInfo - The highest level of licensing (and therefore functionality) in the ArcGIS Desktop product line. (Wikipedia - March 2010) Also see ArcEditor and ArcView. Click for a detailed comparison between the different licensing levels. A more general comparison of the functionality.

ArcMap - One of the 3 main components that make up ArcGIS. It is the interface that allows users to view data sets together, perform analysis and create maps. Also see ArcCatalog and ArcToolbox (GIS Centre, Dalhousie University)

ArcToolbox -One of the 3 main components that make up ArcGIS. It is an organized collection of tools for GIS analysis, data management, and data conversion. It is accessed in both ArcMap and ArcCatalog. Also see ArcMap and ArcToolbox.(GIS Centre, Dalhousie University)

ArcView - The entry level licensing level of ArcGIS Desktop. (Wikipedia - March 2010) Also see ArcEditor and ArcInfo. Click for a detailed comparison between the different licensing levels. A more general comparison of the functionality.






Data Frame - A map element that defines a geographic extent, a page extent, a coordinate system, and other display properties for one or more layers in ArcMap. A dataset can be represented in one or more data frames. In data view, only one data frame is displayed at a time; in layout view, all a map's data frames are displayed at the same time. Many cartography texts use the term "map body" to refer to what ESRI calls a data frame.


E00 - Is ArcInfo's interchange format. It is used to enable a coverage, grid, TIN and associated INFO tables to be transferred between different machines. (ESRI website - March 2010)

Easting - The distance east of the origin that a point in a Cartesian coordinate system lies, measured in that system's units.



Geodatabase - A database or file structure used primarily to store, query, and manipulate spatial data. Geodatabases store geometry, a spatial reference system, attributes, and behavioral rules for data. Various types of geographic datasets can be collected within a geodatabase, including feature classes, attribute tables, raster datasets, network datasets, topologies, and many others. Geodatabases can be stored in IBM DB2, IBM Informix, Oracle, Microsoft Access, Microsoft SQL Server, and PostgreSQL relational database management systems, or in a system of files, such as a file geodatabase.

GIS - Acronym for geographic information system. An integrated collection of computer software and data used to view and manage information about geographic places, analyze spatial relationships, and model spatial processes. A GIS provides a framework for gathering and organizing spatial data and related information so that it can be displayed and analyzed.

Graticule - A network of longitude and latitude lines on a map or chart that relates points on a map to their true locations on the earth.




Inset Map - A small map set within a larger map. An inset map might show a detailed part of the map at a larger scale, or the extent of the existing map drawn at a smaller scale within the context of a larger area.




Key Map - A generalized, smaller-scale map that shows the limits of another map's extent along with its surrounding area. Also referred to as an Overview Map


Label - In ArcGIS, descriptive text, usually based on one or more feature attributes. Labels are placed dynamically on or near features based on user-defined rules and in response to changes in the map display. Labels cannot be individually selected and modified by the user. Label placement rules and display properties (such as font size and color) are defined for an entire layer.

Latitude - The angular distance, usually measured in degrees north or south of the equator. Lines of latitude are also referred to as parallels.

Layout View - In ArcMap and ArcReader, a view that shows the virtual page upon which geographic data and map elements, such as titles, legends, and scale bars, are placed and arranged for printing.

Longitude - The angular distance, usually expressed in degrees, minutes, and seconds, of the location of a point on the earth's surface east or west of an arbitrarily defined meridian (usually the Greenwich prime meridian). All lines of longitude are great circles that intersect the equator and pass through the North and South Poles.




Northing - The distance north of the origin that a point in a Cartesian coordinate system lies, measured in that system's units.




Projection - A method by which the curved surface of the earth is portrayed on a flat surface. This generally requires a systematic mathematical transformation of the earth's graticule of lines of longitude and latitude onto a plane. Some projections can be visualized as a transparent globe with a light bulb at its center (though not all projections emanate from the globe's center) casting lines of latitude and longitude onto a sheet of paper. Generally, the paper is either flat and placed tangent to the globe (a planar or azimuthal projection) or formed into a cone or cylinder and placed over the globe (cylindrical and conical projections). Every map projection distorts distance, area, shape, direction, or some combination thereof.




Raster - A spatial data model that defines space as an array of equally sized cells arranged in rows and columns, and composed of single or multiple bands. Each cell contains an attribute value and location coordinates. Unlike a vector structure, which stores coordinates explicitly, raster coordinates are contained in the ordering of the matrix. Groups of cells that share the same value represent the same type of geographic feature.


Scale - The ratio or relationship between a distance or area on a map and the corresponding distance or area on the ground, commonly expressed as a fraction or ratio. A map scale of 1/100,000 or 1:100,000 means that one unit of measure on the map equals 100,000 of the same unit on the earth.

Scale Bar - A map element used to graphically represent the scale of a map. A scale bar is typically a line marked like a ruler in units proportional to the map's scale.

Shapefile - A vector data storage format for storing the location, shape, and attributes of geographic features. A shapefile is stored in a set of related files and contains one feature class.


Table of Contents - In ArcGIS, a tabbed list of data frames and layers (or tables) on a map that shows how the data is symbolized, the source of the data, and whether or not each layer is selectable.


UTM - Acronym for universal transverse Mercator. A projected coordinate system that divides the world into 60 north and south zones, 6 degrees wide.