Glossary of GIS Terms

ESRI - Environmental Systems Research Institute

Environmental Systems Research Institute. ESRI is the company that makes Arc/INFO, Arc/View and many other related software for GIS.

Common ESRI Terms

ESRI is the company that makes Arc/INFO, Arc/View and many other related software for GIS.

Arcs

Lines that begin and end with a node. Intersections of arcs are always connected with a node. Arcs also make up part of a polygon. An example of data that would use this form would be roads.

Node

Beginning, connecting and ending points of an arc. An example of data that would be represented by this form would be manholes or inlets in a stormwater system.

Point

A single "dot" location. A point is also called a "label point". A label point is the element that holds information in the polygon. An example of data that would be stored in the system using this form would be fire hydrants, or a set of individual address locations.

Polygon

An arc that closes on itself to make a circle or a closed shape. An example of a set of data that would be stored in the GIS in this format would be parks or lakes.

ArcView

Desktop GIS software developed by ESRI used to do some basic GIS operations and print maps.

Shapefile

A set of files that contain a set of points, arcs, or polygons (or features) that hold tabular data and a spatial location. This file format is used in ArcView software. - A set of files that contain a set of points, arcs, or polygons (or features) that hold tabular data and a spatial location. This file format is used in ArcView software.

Arc/INFO

The GIS software developed by ESRI that is used to do more robust GIS operations

Common GIS Terms

Coverage

A file format used in Arc/INFO software developed by ESRI that contain a set of points, arcs, or polygons (or features) that hold tabular data and a spatial location.

Area

A description of the dimension or content of a polygon.

Coordinate System

A fixed reference framework superimposed onto the surface of an area to designate the position of a point within it by using x and y coordinates. The State Plane Coordinate System and the system of latitude and longitude used on the Earth's surface are common examples.

Data

A collection of facts, concepts or instructions in a formalized manner suitable for communication or processing by human or automatic means. Generally used in the GIS field as a reference to all spatial information.

Feature

A spatial element which represent a real-world entity by having specific characteristics. Often used synonymously with the term object. A generalized description of a point, line or polygon.

Field

A location in a data record in which a unit of information is stored. For example, in a database of addresses, one field would be 'city'.

Geocoding

The process by which the geographic coordinates of a location are determined by its address, postal code, or other explicitly non-geographic descriptor.

Legend

The description of the symbology representing features on a map.

Map

A graphic representation of geographically distributed phenomena. The information displayed may be in the form of symbols or signs.

North Arrow

The graphical representation of which direction north is on the map.

Scale

The ratio or fraction between the distance on a map, chart or photograph and the corresponding distance in the real world.

Scale Bar

A map element which shows the scale of a map graphically.

Set

A group of features and their data.

Spatial

An adjective. Of, relating to, or occurring in space.

Table

A means of organizing data in rows and columns in which each row represents an individual entity, record, or feature and each column represents a single field or attribute value.

Query

A way of selecting features based on a set of common characteristics. For example, the act of selecting all the buildings that have an area greater than 2000 sq. ft. out of a database.