Geographic Information Systems

Patty McGrayUniversity of Phoenix

EDTC 560 Applications of Multimedia and Web Page Design

Janet WrightNovember 17, 2004

What is a GIS? An integration of five components

GIS functions

QueryQuery

AnalyzeAnalyze

StoreStore

DisplayDisplay

CaptureCapture

OutputOutput

Buildings

Streets

Reality

Customers

Capturing data

GISData

GPSGPS

480585.5, 3769234.6483194.1, 3768432.3485285.8, 3768391.2484327.4, 3768565.9483874.7, 3769823.0

480585.5, 3769234.6483194.1, 3768432.3485285.8, 3768391.2484327.4, 3768565.9483874.7, 3769823.0

CoordinatesCoordinates

Hardcopy mapsHardcopy mapsDigital dataDigital data

Storing vector data Real-world entities are abstracted into

three basic shapes

Points Points

Retail storesRetail stores

LinesLines

StreetsStreets

Areas/PolygonsAreas/Polygons

Land usesLand uses

Storing raster data Use square cells to model reality Each square holds a value

e.g. Photographs, TV

Reality(A highway)

X,Y

Rows

Columns

Query Identifying specific features

Identifying features based on conditions

Florida counties with a population greater than 300,000

Florida counties with a population greater than 300,000

AnalysisWhich parcels are within 50 feet of the road?

Which parcels are within 50 feet of the road?

Well type Drilled

Building owner Smith

Soil type Sandy

Well type Drilled

Building owner Smith

Soil type Sandy

ProximityProximity

OverlayOverlay

NetworkNetwork

Display

MapsMaps

GraphsGraphs

ReportsReports

Output

DocumentDocument

InternetInternetPaper mapPaper map

GIS Data

ImageImage

Organizing spatial data A GIS works with thematic layers of spatial

data

Answer questions by comparing different layers of data

Components of data Three general components to geographic

information

AttributesAttributesGeometryGeometry

Streets

BehaviorBehavior

Streets and highways may not intersect

Rules:Road nameRoad type

Using your data

The relative position of features determines relationships

I-80 connects San Francisco and New York

I-80 connects San Francisco and New York

San Francisco is contained by California

San Francisco is contained by California

I-80 has length and direction

I-80 has length and direction

New York is adjacent to the Atlantic Ocean

New York is adjacent to the Atlantic Ocean