GIS Dictionary

easting

1 The distance east of the origin that a point in a Cartesian coordinate system lies, measured in ...

edge

1 A line between two points that forms a boundary. In a geometric shape, an edge forms the ...

edit mask

The portion of a coverage where the geometry (or geographical features) has been altered, but where topology has ...

edit task

During editing prior to ArcGIS 10, a setting in the Task drop-down list that determines which operation the ...

EDMS

Acronym for electronic document management system. A computer-based system for organizing, maintaining, and retrieving digital and hard-copy documents. ...

EDN

Acronym for ESRI Developer Network. A subscription program used to acquire ESRI software for developers, which includes a ...

element

In geoprocessing in ArcGIS, a component of a model. Elements can be variables, such as input and derived ...

elevation

The vertical distance of a point or object above or below a reference surface or datum (generally mean sea ...

ellipse

A geometric shape described mathematically as the collection of points whose distances from two given points (the foci) add up ...

ellipsoid

1 A three-dimensional, closed geometric shape, all planar sections of which are ellipses or circles. An ellipsoid has ...

EMF

Acronym for Enhanced Metafile. A spool file format used in printing by the Windows operating system.

empirical

That property of a quantity that indicates that the quantity depends on data, observations, or experiment only; that is, ...

ENC

Acronym for electronic navigational chart. A vector data product used for nautical navigation. ENC data is produced by nautical ...

enclosure

A file describing the contents of an item included in metadata. Enclosing files in metadata works the same ...

encoding

The recording or reformatting of data into a computer format. Data may be encoded to reduce storage, increase ...

enhancement

In remote sensing, applying operations to raster data to improve appearance or usability by making specific features more ...

envelope

The rectangle surrounding one or more geographical features in coordinate space, determined by the minimum and maximum coordinates in the ...

environment variable

A variable maintained by the operating system and shared among programs. Environment variables function as placeholders for environment information, ...

environmental model

An abstract representation of a complex environmental process, emphasizing relationships and patterns in natural systems. Environmental models allow decision makers ...

erase

In ArcInfo, a command that removes or deletes features from one coverage that overlap features in another coverage.

error

1 A measured, observed, calculated, or interpreted value that differs from the true value or the value that ...

error table

A geodatabase table used by the GIS Data ReViewer to track error information through the quality control process. ...

evaluator

A function that determines attribute values for network elements in a network dataset. If a network source does ...

event

A geographic location stored in tabular rather than spatial form. Event types include address events, route events, x,y ...

event table

A data source containing location information in tabular format (called events) that is used to create a spatial ...

explode

An editing process that separates a multipart feature into its component features, which become independent features.

exponent

In mathematics, a number that indicates how many times a base value is multiplied by itself. Exponents are usually ...

export

To move data from one computer system to another, and often, in the process, from one file format to ...

export

To move data from one computer system to another, and often, in the process, from one file format to ...

expression

A sequence of operands and operators constructed according to the syntactic rules of a symbolic language that evaluates to a ...

extension

In ArcGIS, an optional software module that adds specialized tools and functionality to ArcGIS Desktop. ArcGIS Network Analyst, ...

extent

The minimum bounding rectangle (xmin, ymin and xmax, ymax) defined by coordinate pairs of a data source. All coordinates for ...

extraction guide

A specification that defines parameters for feature extraction and attribution. Specifications typically include the size of features to ...

extrusion

The process of projecting features in a two-dimensional data source into a three-dimensional representation: points become vertical lines, ...