Nova Scotia's
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Glossary of Terms and Terminology

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

- Acronyms (not indexed)-

Glossary of Terms and Terminology

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

A

Absolute Accuracy

Refers to the position of an object position in relation to a control survey network. (See also Accuracy and Compare with Relative Accuracy.)

Absolute Coordinate

Coordinate in a unified reference system expressed in the geographic or the X,Y,Z geocentric system.

Access Key

A key that permits access to a particular record stored in a database.

Access Time

The time needed to retrieve data from computer storage.

Accuracy

1. The degree to which an estimated/measured value approaches the actual/true value.

2. Degree of conformity with a standard, or the degree of correctness attained in a measurement. Accuracy relates to the quality of a result, and is distinguished from precision which relates to the quality of the operation by which the result is obtained. (Compare with precision).

3. Degree of precision of the digital topographic information compared to its corresponding reference to the geodetic network. Accuracy of geometric representation assocaited with an entity and the real position of the corresponding topographic feature, as measured with respect to the geodetic network

Accuracy Requirement

Statement of how accurate the desired results must be to support a particular application.

Accuracy Standards

Specifications that set up standards to which the finished product must adhere.

Address

1. A term that generally refers to a location within the computer's storage. The term is normally used in the context of retrieving or storing data.

2. The location of a building or parcel of land.

3. With respect to a start or road network - address may refer to either the owners location or the physical location of a building (See also Civic Address and Owner Address)

Aerial Photography Database

A database (library) of photographic negatives and prints of provincial aerial photography acquired over the past fifty or more years. The individual photographs can be referenced to the NSCRS to provide the positional accuracy required by users for mapping, resource inventory or other uses. This database is in hardcopy format (film and/or paper) and represents a unique and irreplaceable resource to the province.

Aggregation

Process of bringing together many distinct parts or categories of data into one composite grouping. In a GIS, the results of data aggregation are often displayed graphically. (Compare with Disagggregation).

Algorithm

A series of instructions or procedural steps leading to the solution of a particular problem.

Alphanumeric

Consisting of both letters and numbers, and possibly including other symbols such as punctuation marks. (Compare with ASCII).

Altimetry

Determination of height by measurement of air pressure.

AMF (Area Master File)

A data file available from Statistics Canada that provides a street and block address and a reference for various statistical entities. Now referred to as SNF (Street Network File).

Analog

Representation of a numerical quantity by continuously variable physical qualities such as graphic marks or electric voltages. (Contrast with Digital).

Analysis

Methodological investigation of a problem by a consistent procedure, and its separation into related units for further detailed study. In GIS some examples of analysis are: Neighbourhood Analysis; Overlay Analysis; View Shed Analysis.

Annotation

Any marking used for the purpose of clarification. This can include numbers, letters, symbols, and signs; eg the name of a town or river could be considered map annotation. (See also Label).

Application

A program or an assembly of software programs to support a specific operation.

Application Programming

The process of using programming languages to solve problems or simulate events. This is in contrast to system programming, which is concerned with events related to efficient functioning of hardware and software. System programs support application programs.

Arc

1. A topological primitive that is defined by two or more X,Y coordinates. Arcs are elements in a network and may be topologically linked to form the boundaries of polygons. Also referred to as Edge. (Compare with Line)

2. A curve defined by an analytical equation

Archival Storage

Magnetic or optical media (tapes, removable disks) used to store programs and data outside the normal addressable memory units of a computer.

Arc/Info

See Geographic Information System.

Arc View

See GIS Query Tool.

Area

Geometric representation of a surface; entity that is composed of a line or a series of lines used for its delineation. A polygon on the earth as projected onto a horizontal plane is an example of an area. The size or extent of an area is expressed in length units square. (Compare with Polygon)

Artifical Intelligence (AI)

A branch of computer science dealing with the formalization of cognitive processes.

ASCII

1. American Standard Code for Information Interchange, commonly used in transferring alphanumeric [textual] data for normal data processing activities. (Compare with Alphanumeric)

2. A standard encoding scheme used on many computers for converting alphanumeric codes into 7 bit signatures. (Compare with Alphanumeric)

Aspect

Horizontal direction in which a slope faces commonly expressed as the direction clockwise from north.

Aspect Ratio

Numerical ratio of picture width to height when discussing video displays.

Assembly Language

A low-level, primitive programming language that uses mnemonics rather than English-like statements. Assembly language statements are translated on a one-to-one basis to machine language statements.

Assessment Neighbourhood

Asynchronous Communication

A mode of data communication in which start and stop elements at the beginning and end character independently control the data stream.

Atlas Pro

See Desktop Mapping Software.

Attribute

A defined characteristic or item of information that describes an element. Non-locational information associated with a node, arc, or polygon feature in a GIS.

Attribute Accuracy

The accuracy or reliability of attribute data within the limits described by feature completeness. If attribute accuracy information is not available in the above form, a description of known attribute accuracy characteristics may be substituted.

Attribute Dictionary

See Data Dictionary.

Attribute Label

See Label.

Attribute Tagging

Process of assigning an attribute to a particular feature.

Automated Cartography

The process of drawing maps with the aid of computer driven input and display devices such as plotters and graphics screens. The term does not imply any information processing.

Automated Mapping

The use of computer graphics systems to create, edit and manipulate cartographic data. The resulting graphic image files are a compilation of "primitive" drafted features with no information processing capabilities other than to generate displays of different combinations of map data, views, and scales

Auxiliary Storage

Addressable memory devices outside the main memory of a computer such as disks and tape units. Also referred to as external memory or secondary storage.

Average Terrestrial System 1977 (ATS 77)

The geocentric reference ellipsoid / datum used by LRIS to replace NAD 27. (See also Datum)

Azimuth

Direction of a line given as an angle measured clockwise from a reference direction, usually north.

B

Base Data

Basic level of map data on which other information is placed for purposes of comparison or geographical correlation. (Also called Base Layer.)

Base Layer

See Base Data.

Base Map

A map which displays planimetric and /or topographic information and which may be used as a base for a thematic layer. Features which may be included on a base map are: roads, rivers, major structures (buildings), contours, etc. Feature presentation will, however, be map scale dependent.

BASIC

See High-level Language.

Batch Processing

The processing of a group of applications on the computer without operator intervention.

Bathymetry

Contours of depth (of the water) describing the shape of the bottom of a water body. (Also referred to as Isobaths.)

Baud Rate

A measure of the speed of data transmission between a computer and other devices. e.g. On a serial line it is the equivalent to bits per second. On a parallel line the baud rate is equivalent to bytes per second.

Bearing

Horizontal angle at a given point measured clockwise from a specific reference datum to a second point.

Benchmark

A set of criteria used to evaluate the capabilities of a hardware and/or software system.

Benchmark Test

A test to evaluate the capabilities of a computer system in terms of the customer's requirements.

Big Endian

Byte order in which the most significant byte of data is stored first. (Compare with Little Endian)

Bit

The smallest unit of information that can be stored and processed in a computer. A bit may have one of two values 0 or 1; i.e. yes/no, true/false, on/off.

Bit Map

A pattern of bits on a grid used to generate an image.

Bits Per Inch (BPI)

The density of bits recorded on a magnetic tape; e.g. 800, 1600, and 6500 are common standards. It is in fact equivalent to bytes per inch on a tape since a byte is stored lengthwise across the tape.

Bits Per Second (BPS)

See Baud Rate.

Black Box

A machine, the working of which is unknown to the user, but which gives answers to problems when provided with certain input information.

Block

1. Group of disk or tape records that is stored and transfered as a single unit.

2. Group of bits or characters that is transimtted as a unit

3. Group of text characters that has been marked for moving, copying, saving or other operation.

Block Length

The size of a block measured in the number of characters, words or records it contains.

Blow Patch

Small area of information spliced into a database in order to update, complete, or densify the data content.

Boolean Logic

A logic, or algebra, that is particularly important in data retrieval and analysis. It uses the comparative operations "AND,""OR,""EITHER/OR," and "NOT" to determine whether two data sets are related (TRUE/YES) or unrelated (FALSE/NO).

Boot

To start or restart the operating system of a computer by the computer's own actions. (Also known as Bootstrap.)

Boundary/Boundary Line

1. Anything referred to in the description of a land parcel which identifies on the ground the limits of the parcel.

2. The legal limit/demarcation between two units of land. Also referred to as Legal Boundary.

3. Every separation, natural or artifical, which marks the confines or line of division of two continuous estates.

4. A line that is a border of one or two areas.

Bounding Rectangle

See Minimum Bounding Rectangle.

Breakline

A graphic defining a sharp contrast change in the slope of the land. e.g. embankment.

Breakpoint

The location in a contour line marking the intersection with a linear feature.

Browse

To be able to select and take a quick look, at part of a map or database to check for features of interest. Usually no analysis or data manipulation is involved.

Buffer

1. An area of temporary data storage.

2. Compilation of distance zones from a selected coverage feature (which may be a point, line, or polygon). This operation includes the rebuilding of topology for the new coverage with the distance zones (buffers) defined as polygons. (See also Corridor)

Bug

An error in a computer program or in a piece of electronics that causes it to function improperly.

Bulletin Boards

Systems on computer networks where users can deposit and read messages.

Bus

A circuit, or group of circuits, that provide a communication path between the computer and peripherals.

Byte

A group of continuous bits, usually eight, that represent a character and which are operated on as a unit. The number of bytes is used to measure the capacity of memory and storage units; e.g 256 Kbyte, 300 Mbyte. 1 Kbyte = 1024 Bytes; 1 Meg = 1024 Kbytes; 1 Gbyte = 1024 Mbytes.

Byte Order

A hardware implementation of an encoding scheme. It determines the order in which bytes are stored in a long word. (See Little-endian and Big-endian)

Bytes Per Second

See Baud Rate.

C

C

See High-level Language.

C+

See High-level Language.

C++

See High-level Language.

CAD

See Computer Aided Design.

Cadastral

1. Concerning any land-related tenure, whether surface or sub-surface and whether linear, parcel-based or defined as a single point.

2. The set of features comprising the boundaries delimiting interests in land, and the polygons and labels pertaining thereto.

Cadastral Layer

A set of information depicting the pattern of land ownership rights in an area.

Cadastre

A record of interests in land.

Canadian Base Network (CBN)

The very high accuracy, multi-dimensional network of stations being established within Canada through the cooperative efforts of the Federal and provincial governments. It is the Canadian replacement of the convetnional geodetic triangulation network and is based upon high precision GPS. (Also referred to as High Precision Network or HPN.)

Cardinal Points

Principal directions. In GIS applications this usually consists of N, NE, E, SE, S, SW, W, NW.

Cardinality

A two digit expression that represents the minimum and maximum number of times one occurrence of an entity, a geometric representation or ancillary data can be involved in a relation. If the maximum value is undetermined, it is identified by the letter N.

CARIS Access

See GIS Query Tool.

CARIS GIS

See Geographic Information System.

Cartesian Coordinate System

Coordinate system in which the location of points in space are given by reference to three orthogonal planes, normally referred to as X, Y, Z.

Carto Base

See Cartographic Database.

Carto Database

See Cartographic Database.

Cartographic Database

A mosaic of cartographically edited topographic files, clipped to the bounds of windows as defined for a specific map series. The Cartographic Database is not suited to GIS analysis. (Also referred to as Carto Database, and Carto Base.)

Cartographic Enhancement

Addition of names, boundaries, and other information to a map to enhance visual presentation. (Also referred to as Cosmetic Enhancement.)

Cartographic Feature

A term applied to the natural or cultural objects shown on a map or chart.

Cartographic File

A processed file of cartographic information in digital form.

Cartographic Primitive

See Text Primitive.

Cartography

The study of maps, including the art and technology of map making.

CCITT

Comite Consultatif Internationale de Telegraphie et Telephonie, an organization based in Geneva, Switzerland. The CCITT recommends use of communications standards that are recognized throughout the world.

Cell

Most basic element of information in a raster or grid description of spatial elements. Its shape is usually rectangular and it has an implicitly defined size and geographic position. (Also referred to as a pixel.)

Central Meridian

The meridian that passes through the poles and origin of an ellipsoid/sphere representing the earth and is used in calculations of a specific projection.

Central Processing Unit (CPU)

The principal operating component of a computer. It is usually defined as the combination of the Arithmetic and Logic Unit (ALU), the Control Unit (CU) and the main memory.

Centroid

In terms of polygons, the geographic centre or the average of the x and y values making up the perimeter points. Where it is used to locate a polygon and its label, this term has been generalized so that the point may occur at any point in the polygon, in order to ensure its inclusion within the polygon and thus is called a false centroid. (Compare with Label Point)

Character

An alphabetical, numerical, or graphic symbol stored or processed by computer equipment and that is treated as a single unit of data.

Character Generator

Hardware which will generate a finite set of characters onto a display surface.

Character Recognition

See Optical Character Recognition.

Characters Per Second (CPS)

A measure of the speed with which a device (usually a printer or a VDU) can process data in the form of characters.

Check Points

1. Any set of points, not included in the creation of a matehmatical model, which are subsequently used to check the accuracy of the model. For example: Spot elevations.

2. Spot elevations read throughout the file to provide an independent check of the DTM and / or generated contours. [NB DTM Users Guide]

Chip

An integrated circuit device including its encapsulating package and circuit terminations.

Choropleth Map

A map that shows statistics related to geographical areas by shading the areas based on statistical values.

Chromatic

Of or relating to colour or colour phenomena; multicolored.

Civic Address

A geo-reference providing a physical location of a building or parcel in relation to its surroundings.

Classification

1. The systematic grouping of attributes or entities into categories that are distinguished by a shared characteristic.

2. The process of identifying a set of features as belonging to a group.

Cleaning

Manual activity to check and repair information accuracy prior to conversion. (Also referred to as Scrubbing.)

Clipping

Elimination of parts of a data layer either inclusive or exclusive of given limits.

COBOL

See High-level Language.

Code

1. In computing, the instructions or statements of a program, or the act of generating them.

2. A set of rules outlining the way in which data may be represented.

Code Table

A set of character specifications. A code table defines the alphanumeric and special characters that are used in a computer system to model written languages.

COGO (Coordinate Geomerty)

A set of procedures for encoding and manipulating bearings, distances and angles of survey data into a graphic representation. It is also a frequently a subsystem of a GIS.

Colour Fill

Method of filling areas with colour.

Column

See Field.

Command Language

A source language consisting principally of procedural operations, each capable of invoking a function to be executed.

Command Line

Location on a computer screen where commands are entered.

Common Business Oriented Language (COBOL)

See Third Generation Language.

Compact Disk

A media used to store data and read with laser light.

Compatibility

The ability of two devices to work together. In addition, if all programs can be run successfully without alteration on two different computers, then the computers are generally said to be compatible.

Compiler

A computer program that translates a high-level programming language, such as FORTRAN or PASCAL into computer instructions.

Completeness

an assessment of content and coverage. See also Spatial Completeness and Content Completeness.

Complex Area

A specific kind of area that involves a complex geometry. This type of area is formed of inclusive and exclusive lines. Inclusive lines define the external delimitation of the area, while exclusive lines delimit the internal zones to be excluded. (Also known as complex polygon.)

Complex Feature

A feature that includes simple or other complex features. For instance, a watershed complex feature may include wells, rivers, and lakes as simple features (points, lines, and areas, respectively).

Complex Feature Class

A feature class that includes two or more other feature classes (simple or complex).

Complex Polygon

See Complex Area.

Composite Map

A single map created by joining together several separately digitized maps.

Compound Key

A group of columns used together to create a key in a relational table.

Compression

A series of techniques used for the reduction of space, bandwidth, cost, transmission, generating time, and the storage of data. These techniques are designed for the elimination of repetition, removal of irrelevancies, and the employment of special coding techniques, such as run-length encoding.

Computer

A set of related hardware and software that allows the input, storage, manipulation, and output of data.

Computer Access

The ability to obtain data or programs from, or place them in, computer storage.

Computer Aided Design (CAD)

Software with the capability of assisting the operator to perform standard engineering and architecture design functions. Examples of CAD software include AutoCad, and Intergraph Microstation.

Computer Aided Mapping

See Computer Assisted Cartography.

Computer Assisted Cartography

The process of producing cartographic output through the use of computers. (Also called Computer Aided Mapping)

Computer Compatible Format

Data in a format which can be readily input into a computer.

Computer Graphics

A general term embracing any computing activity that results in graphic images.

Computing Environment

The total range of hardware and software facilities provided by a host computer and its operating system.

Conceptual Data Model

A model that reflects information about entities of ongoing interest to the enterprise. These entities are grouped together based on their usage and applications.

Confidence Interval

Statement of accuracy based on a statistic whose distribution function is known. Errors are stated as some percentage of the total probability of 100 percent.

Configuration

A particular combination of computer hardware and software for a certain class of application tasks.

Conflation

The process of reconciling the position of corresponding features (purported to be colocated and / or the same) in different data layers. Conflation functions are used to reconcile these differences so that the correcponding features overlay precisely.

Connected Node

One of the two node primitive types used to represent linked features that are zero dimensional at a particular scale. Connected nodes are always found at the ends of arcs and are topologically linked to the arcs.

Connectivity Analysis

Analytical technique to determine whether a set of points (nodes) or lines are connected to each other.

Console

A device that allows the operator to communicate with the computer.

Content Completeness

The degree to which information is complete with reference to a specification.

Contiguity

The state of being near or touching.

Continuous Database

See Seamless Database

Contour

An imaginary line on the ground, all points of which are at the same elevation above or below a specified datum surface, usually mean sea level.

Contour Interval

Difference of elevation between two consecutive contours. In general, one contour interval is used per data set.

Contrast

The relationship of the brightest to the darkest portions of a display image.

Control

A system of points which are used as fixed references for positioning other surveyed features.

Control Point

1. Any station in a horizontal or vertical control network that is identified in a data set or photograph and used for correlating the data shown in that data set or photograph.

2. A permanently fixed point on the ground, the location of which has been accurately determined and recorded for referencing of future surveys, which may include aerial photography. (Also referred to as Grid Monument or Nova Scotia Control Monument.)

3. A permanently fixed point on the ground with mathematically adjusted 3 dimensional positional values used to accuractely reference information on the earth. Physical characteristics of a control point may vary from a metal stake in the ground to a marker set in concrete or bedrock to a brass plate embedded in a pillar. (Also referred to as a grid monument or Nova Scotia Control Monument(NSCM) or Survey Control Point).

Controller

An interface between a host computer and a peripheral.

Contour Map

Topographic map at any scale which includes contour lines. (Compare with Planimetric Map.)

Conventional Map

Map produced and manitained by traditional [manual] cartographic methods.

Coordinate Array

A fixed-length list of coordinate tuples.

Coordinate Pair

A specified position in a two-dimensional grid, where the first position relates to the X axis and the second position relates to the Y axis.

Coordinate String

A variable-length list of coordinate tuples.

Coordinate System

A particular kind of reference frame or system, such as plane rectangular coordinates or spherical coordinates, that use linear or angular quantities to designate the position of points within that particular reference frame or system.

Coordinate Triplet

A specified position in a three dimensional grid, where the first position relates to the X axis, the second position relates to the Y axis, and the third position relates to the Z axis.

Coordinate Tuple

A coordinate pair or triplet. (See also Tuple)

Coordinates

A system of two or more numbers that specify the position of a point in a coordinate system.

Core Memory

See Main Memory.

Corporate Applications

Applications that manage and provide access to data in the corporate domain. They are accessible to or support all land information infrastructure users.

Corporate Data

Data that is or could be used by 2 or more organizations. In the context of a provincial land information system the terms corporate data and corporate land-related data are often interchanged

Corporate Land Information

See Corporate Land-Related Data.

Corporate Land-Related Data

Land related data that is or could be used by two or more organizations. (Also referred to as Corporate Land Information.)

Corporate Technology

Technology which is required to support the data access and exchange applications of the land information infrastructure that move both corporate and participatory data.

Corridor

An area of uniform width bordering both or one side of a lineal feature such as a stream or road. (See also Buffer.)

Corridor Generation

To automatically outline a corridor along a defined linear feature .

Cosmetic Enhancement

See Cartographic Enhancement.

County

1. A court administrative region as established by provincial statute in the eighteenth or nineteenth century, before the establishment of the rural municipalities.

2. Geographic regions used for the delivery of provincial and municipal government programs.

Coverage

See Data Layer.

CPU Time

Actual computational time necessary to process a set of instructions in the arithmetic and logic units of the computer.

Crash

An unexpected computer failure that demands user intervention or professional maintenance.

Cross-hatching

The technique of shading areas on a map with a given pattern of lines or symbols.

Cross-section

A section taken at right angles to the direction of a proposed centerline.

Cross-tile Topology

The encoding of topological relationships in such a manner that those relations are maintained even when a data layer has been physically partitioned into multiple tiles. (Compare with Seamless Database)

Currency

Time during which an item is up-to-date.

Cursor

A visible symbol guided by a keyboard, joystick, tracking ball, or digitizer, usually in the form of a cross or blinking symbol, that indicates a position on a computer screen. (Also refers to the keypad and cross-hair assembly used on a digitizing table to capture the coordinates of mapped information.)

Curvature

Mathematically, is the second derivative of terrain elevation. Is an important feature in shape analysis and is used to indicate convexity/concavity of a surface.

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