Gis Test 1

Front 1

Data exploration

Back 1

Data-centred query & analysis.

Front 2

Dynamic segmentation

Back 2

A data model that allows the use of linearly measured data on a coordinate system.

Front 3

Geographic Information System (GIS)

Back 3

A computer system for capturing, storing, querying, analyzing and displaying geospatial data.

Front 4

Georelational data model

Back 4

A vector data model that uses a split system to store geometries and attributes.

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Geospatial data

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Data that describe both the locations and characteristics of spatial features on the Earth's surface.

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Object-based data model

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A data model that uses objects to organize spatial data and stores geometries and attributes in a single system.

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Raster data model

Back 7

A data model that uses a grid and cells to represent the spatial variation of a feature.

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Relational database

Back 8

A collection of tables in which tables are connected to one another by keys.

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Topology

Back 9

A subfield of mathematics that, when applied to GIS, ensures the spatial relationships between features are expressed explicitly.

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Triangulated irregular network (TIN)

Back 10

Composite vector data that approximate the terrain with a set of non overlapping triangles.

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Vector data model

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A spatial data model that uses points and their coordinates to construct spatial features of points, lines and polygons.

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Azimuthal projection

Back 12

One type of map projection that retains certain accurate directions. Azimuthal also refers to one type of map projection that uses a plane as the projection surface.

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Central lines

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The central parallel and and the central meridian. Together, they define the center or origin of a map projection.

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Conformal projection

Back 14

One type of map projection that preserves local shapes.

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Conic projection

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One type of map projection that uses a cone as the projection surface.

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Cylindrical projection

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One type of map projection that uses a cylinder as the projection surface.

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Datum

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The basis for calculating the geographic coordinates of a location. An ellipsoid is a required input to the derivation of a datum.

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Datum shift

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A change of one datum to another, such as from NAD27 to NAD83, which can result in substantial horizontal shifts of point positions.

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Decimal degrees (DD) system

Back 19

A measurement system for longitude and latitude values such as 42.5°.

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Degrees-minutes-seconds (DMS) system

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A measurement system for longitude and latitude values such as 42°30'00'', in which 1 degree equals 60 minutes and 1 minute equals 60 seconds.

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Ellipsoid

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A model that approximates the Earth. Also called spheroid.

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Equidistant projection

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One type of map projection that maintains consistency of scale for certain distances.

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Equivalent projection

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One type of map projection that represents areas in correct relative size.

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False easting

Back 24

A value applied to the origin of a coordinate system to change the x-coordinate readings.

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False northing

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A value applied to the origin of a coordinate system to change the y-coordinate readings.

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Geographic coordinate system

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A location reference system for spatial features on the Earth's surface.

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GRS80

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A sattelite-determined ellipsoid for the Geodetic Reference System 1980.

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Lambert conformal conic projection

Back 28

A common map projection.

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Latitude

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The angle north or south of the equatorial plane.

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Longitude

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The angle east or west from the prime meridian.

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Map projection

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A systematic arrangement of parallels and meridians on a plane surface.

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Meridians

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Lines of longitude that measure locations in the E-W direction on the geographic coordinate system.

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Parallels

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Lines of latitude that measure locations in the N-S direction on the geographic coordinate system.

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Principle scale

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Same as the scale of the reference globe.

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Projected coordinate system

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A plane coordinate system that is based on a map projection.

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Projection

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The process of transforming the spatial relationship of features on the Earth's surface to a flat map.

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Reference globe

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A reduced model of the Earth from which map projections are made. Also called nominal or generating globe.

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Reprojection

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Projection of spatial data from one projected coordinate system to another.

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Scale factor

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Ratio of the local scale to the scale of the reference globe. The scale factor is 1.0 along a standard line.

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Speroid

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A model that approximates the Earth. Also called ellipsoid.

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Standard line

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Line of tangency between the projection surface and the reference globe. A standard line has no projection distortion and has the same scale as that of the reference globe.

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Standard meridian

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A standard line that follows a meridian.

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Standard parallel

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A standard line that follows a parallel.

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Transverse Mercator projection

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A common map projection, which is the basis for the UTM grid system.

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Universal Polar Stereographic (UPS) grid system

Back 45

A grid system that divides the polar area into a series of 100 000-meter squares, similar to the UTM grid system.

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Universal Transverse Mercator (UTM) grid system

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A coordinate system that divides the Earth's surface between 84°N and 80°S into 60 zones, with each zone further divided into the northern hemisphere and the southern hemisphere.

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WGS84

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A satellite-determined ellipsoid for the World Geodetic System 1984.

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x-shift

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A value applied to x-coordinate readings to reduce the number of digits.

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y-shift

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A value applied to y-coordinate readings to reduce the number of digits.

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Cartography

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The making and study of maps in all their aspects.

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Chart map

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A map that uses charts such as pie charts or bar charts as map symbols.

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Chloropleth map

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A map that applies shading symbols to data or statistics collected for enumeration units such as countries or states.

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Chroma

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The richness or brilliance of a color. Also called saturation or intensity.

Front 54

CMYK

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A colour model in which colours are specified by the four process colours:

*Cyan

*Magenta

*Yellow

*Black

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Contrast

Back 55

A basic element in map design that enhances the look of a map or the figure-ground relationship by varying the size, width, colour and texture of map symbols.

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Dasymetric map

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A map that uses statistics and additional information to deliniate areas of homogenous values, rather than following administrative boundaries.

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Dot map

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A map that uses uniform point symbols to show spatial data, with each symbol representing a unit value.

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Figure-ground relationship

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A tendency in visual perception to separate more important objects in a visual field from the background.

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Flow map

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A map that displays different quantities of flow data by varying the width of the line symbol.

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General reference map

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One type of map used for general purposes such as the USGS topographic map.

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Graduated colour map

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A map that uses a progressive colour scheme such as light red to dark red to show the variation in geospatial data.

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Graduated symbol map

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A map that uses different-sized symbols such as circles, squares or triangles to represent different magnitudes.

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HSV

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A colour model in which colours are specified by their hue, saturation and value.

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Hue

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The quality that distinguishes one colour from another, such as red from blue. Hue is the dominant wavelength of light.

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Interposition

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A tendency for an object to appear as though it is behind or below another object because of its incomplete outline.

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Isarithmic map

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A map that uses a system of isolines to represent a surface.

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Layout

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The arrangement and composition of map elements on a map.

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LCD (liquid crystal display) screen

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A display device for a PC that uses electric charge through a liquid crystal solution between two sheets of polarizing materials.

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Map design

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The process of developing a visual plan to achieve the purpose of a map.

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Point

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Measurement unit of type, with 72 points to an inch.

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Proportional symbol map

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A map that uses a specific-sized symbol for each numeric value.

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RGB

Back 72

A colour model in which colours are specified by their red, green and blue components.

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Sans serif

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Without serif

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Serif

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Small, finishing touches added to the ends of line strokes in a typeface.

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Spline text

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A text string aligned along a curved line.

Front 76

Subdivisional organization

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A map design principle which groups map symbols at the primary and secondary levels according to the intended visual hierarchy.

Front 77

Thematic map

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One type of map that emphasizes the spatial distribution of population densities by country.

Front 78

Transparency

Back 78

A display tool that controls the percentage of layer to appear apparent.

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Typeface

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A particular style or design of type.

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Type weight

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Relative blackness of a type such as bold, regular or light.

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Type width

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Relative width of a type such as condensed or extended.

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Value

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The lightness or darkness of a colour.

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Visual hierarchy

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The process of developing a visual plan to introduce the 3D effect or depth to maps.

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Arc

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A line connected to 2 end points.

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ArcObjects

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A collection of objects used by ArcGIS

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Area definition

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A topological relationship used in Esri's coverage data format, stipulating that an area is defined by a series of connected arcs.

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Class

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A set of objects with similar characteristics

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Connectivity

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A topological relationship used in Esri's coverage data format, stipulating that arcs connect to each other at nodes.

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Contiguity

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A topological relationship used in Esri's coverage data format, stipulating that arcs have directions and left and right polygons.

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Coverage

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A topological vector data format used in Esri products.

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Encapsulation

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A principle used in object-oriented technology to hide the properties and methods of an object so that the object can be accessed only through the predefined interfaces.

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Event

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An attribute that can be associated and displayed with a route.

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Feature class

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A data set that stores features of the same geometry type in a geodatabase.

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Feature dataset

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A collection of feature classes in a geodatabase that share the same coordinate system and area extent.

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Geodatabase

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An object-based vector data model developed by Esri.

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Georelational data model

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A GIS data model that stores geometries and attributes in two seperate but related file systems.

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Interface

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A set of externally visible operations of an object.

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Line

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A spatial feature that is represented by a series of points and has the geometric properties of location and length. Also called arc or edge.

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Node

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The beginning or end point of a line.

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Object-based data model

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A vector data model that uses objects to organize spatial data.

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Point

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A spatial feature that is represented by a pair of coordinates and has only the geometric property of location.

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Polygon

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A spatial feature that is represented by a series of lines and has the geometric properties of location, size and perimeter. Also called area.

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Regions

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Composite features that can have spatially disjoint components and can overlap one another.

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Route

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A linear feature that allows linear measures to be used on a projected coordinate system.

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Shapefile

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A nontopological vector data format used in Esri products.

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Bi-level scanned file

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A scanned file containing values of 0 or 1.

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Cell-by-cell encoding

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A raster data structure that stores cell values in a matrix by row and column.

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Data compression

Back 108

Reduction of data volume, especially for raster data.

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Digital elevation model (DEM)

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A digital model with an array of uniformly spaced elevation data in raster format.

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Digital ortophoto quad (DOQ)

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A digitized image in which the displacement caused by camera tilt and terrain relief has been removed from an aerial photograph.

Front 111

Digital raster graphic (DRG)

Back 111

A scanned image of a USGS topographic map.

Front 112

Floating-point raster

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A raster that contains cells of continuous values.

Front 113

Georeferenced raster

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A raster that has been processed to align with a projected coordinate system.

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Integer raster

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A raster that contains cell values of integers.

Front 115

Landsat

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An orbiting satellite that provides repeat images of the Earth's surface.

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Lossless compression

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One type of data compression that allows the original image to be precisely reconstructed.

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Lossy compression

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One type of data compression that can achieve high compression ratios, but cannot fully reconstruct the original image.

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Quadtree

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A raster data structure that divides a raster into a hierarchy of quadrants.

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Rasterization

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Conversion of vector data to raster data.

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Run-length encoding (RLE)

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A raster data structure that records the cell values by row and by group.

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Vectorization

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Conversion of raster data to vector data.

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Wavelet transform

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An image compression technique that treats an image as a wave and progressively decomposes the wave into simpler wavelets.

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Cluster tolerance

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A tolerance for snapping points and lines.

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Dangling node

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A node at the end of an arc that is not connected to other arcs.

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Data precision

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A measure of how exactly data such as the location data of x- and y-coordinates are recorded.

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Location errors

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Errors related to the location of map features such as missing lines or missing polygons.

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Overshoot

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One type of digitizing error that results in an overextended arc.

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Pseudo node

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A node appearing along a continuous arc.

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Topological errors

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Errors related to the topology of map features such as dangling arcs and overlapping boundaries.

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Undershoot

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One type of digitizing error that results in a gap between arcs.

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Database management system (DBMS)

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A software package for building and manipulating databases for such tasks as data input, search, retrieval, manipulation and output.

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Feature attribute table

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An attribute table that has access to the geometries of features.

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Field

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A column in a table that describes an attribute of a spatial feature.

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Flat file

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A database that contains all data in a large table.

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Foreign key

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One or more attributes in a table that match the primary key in another table.

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Hierarchical database

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A database that is organised at different levels and uses the one-to-many association between levels.

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Interval data

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Data with known intervals between values, such as temperature readings.

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Join

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A relational database operation that brings together two tables by using keys or a field common to both tables.

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Many-to-many relationship

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One type of data relationship in which many records in a table are connected to many other records in another table.

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Many-to-one relationship

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One type of data relationship in which many records in a table are connected to one record in another table.

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Network database

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A database based on the built-in connections across tables.

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Nominal data

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Data that show different kinds or different categories, such as land types or soil types.

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Normalization

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The process of taking a table with all the attribute data and breaking it down to small tables while maintaining the necessary linkages between them in a relational database.

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One-to-many relationship.

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One type of data relationship in which one record in a table is connected to many other records in another table.

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One-to-one relationship

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One type of data relationship in which one record in a table is connected to one record in another table.

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Ordinal data

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Data that are ranked, such as large, medium and small cities.

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Primary key

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One or more attributes that can uniquely identify a record in a table.

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Ratio data

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Data that have known intervals between values and a meaningful zero value, such as population densities.

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Record

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A row in a table that represents a spatial feature.

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Relate

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A relational database operation that temporarily connects two tables by using keys or a field common to both tables.

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Relational database

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A database that consists of a collection of tables and uses keys to connect the tables.

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Root mean square (RMS) error

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A measure of the deviation between the actual location and the estimated location of the control points in geometric transformation.