Portraying the EarthGPS, RS, and GIS as geographic tools

Lab 3

Concepts

Types of maps Categories of data on maps

Location data Attribute data 3 representations of data

Global Positioning Systems Remote Sensing Geographic Information Systems

Types of Maps

“map”: representation of spatial distribution of selected phenomena

Maps show what is where

General Purpose/Reference maps Display natural & man-made elements on the earth Ex: Landscape features, Political boundaries, etc.

Special Purpose/Thematic/Statistical maps Illustrates characteristics of a geographical area Ex: Population, Unemployment, Ethnicity, etc.

Data on MapsCategories of Data

Location Data: coordinates, addresses “Where is it located?”

Data on MapsCategories of Data

Attribute Data: descriptive & informative “What kind of item is there?” and “How many items are

there?”

Data on MapsWhere does it come from?

Scanned maps Field sampling Aerial photographs Satellite images Databases (location &

attribute information)

Data on MapsThree representations

POINTS single physical item Building, person, tree

LINES “arcs” Street, river, contours

AREAS “polygons” Lakes, political units

“Layers” of data

Global Positioning System (GPS) Satellite-based navigation

system, allows users to find their latitude/longitude location.

24 satellites in orbit (U.S. Dept of Defense).

Originally for military application, but made available for civilian use in 1980s.

Each satellite circles the Earth twice a day.

GPS works in any weather condition, anywhere in the world, 24 hours a day.

Global Positioning System (GPS)Three elementsSpace

Satellites in orbit

Control Ground stations

around the world that upload data to the satellites and control their orbits

User Receiving end of the

satellite transmission information

Global Positioning Systems (GPS)How do they work? Use triangulation to provide

user with location A GPS receiver must be locked

on to the signal of at least 3satellites to calculate latitudeand longitude.

With four or more satellites, the receiver can determine the user's 3D position (latitude, longitude and altitude).

You holdinga GPS receiver

Remote Sensing

Collecting information about the Earth without direct contact

2 examples Satellite Imagery Aerial Photographs

Remote SensingSatellite ImageryRight: Pearl Harbor, Hawai’iFar Right: Italy and GreeceBelow: Light pollution at night

Remote SensingAerial Photography

Below Left: Houston, TXBelow Center: Chicago, ILBelow Right: Turner Field

Geographic Information Systems (GIS) A system of software, hardware, data, and

user which allows us to visualize, manipulate, analyze, and display spatial data

Maps are a product of GIS – a way to spatially visualize the data

Often called “smart maps” because they link databases to a map, with interactive capabilities

GIS is a problem-solver Ask a question Combine various forms of data in a program Interactive capabilities allow for analysis and final map

Geographic Information Systems (GIS)Think of it this way… Data in a database: not easy to interpret

Geographic Information Systems (GIS)But… Data represented and analyzed in a spatial

manner: easier interpretation

Geographic Information Systems (GIS)Example: Atlanta Area Schools

Geographic Information Systems (GIS)Example: Atlanta Area Schools

Geographic Information Systems (GIS)Helpful not just to Geographers Emergency Services

Fire, police, 911 Environmental Agencies

Monitoring environmental quality standards, flooding Business

Marketing, store location analysis, customer data Industry

Transportation, communications, pipelines Government

Census Bureau statistics, historical preservation Education

Geographic Information Systems (GIS)GIS on the InternetWhat is and what isn’t GIS? Think carefully and observe the

tools you have available on each website.

Google Maps http://maps.google.com

National Geographic Map Machine http://plasma.nationalgeographic.com/mapmachine

GEOMAC Wildland Fire Support http://geomac.usgs.gov/viewer/viewer.html

City of Clearwater, Florida http://publicgis.myclearwater.com/imsreports/AddressReportsPickerN.asp

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The European Pollutant Emission Register http://eper.cec.eu.int/eper/flashmap.asp

Downtown Los Angeles Homeless Tracker http://homeless.cartifact.com/