An Introduction to GIS and GPS Technology Bo Shen March 5, 2004.
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Transcript of An Introduction to GIS and GPS Technology Bo Shen March 5, 2004.
An Introduction to GIS An Introduction to GIS and GPS Technologyand GPS Technology
Bo ShenBo Shen
March 5, 2004March 5, 2004
OverviewOverview What is GIS?What is GIS?
GIS Application GIS Application GIS DataGIS Data GIS Technology(ArcGIS)GIS Technology(ArcGIS)
What is GPS?What is GPS? What does the GPS do? How it worksHow it works
Application with GIS and GPSApplication with GIS and GPS Pocket StreetPocket Street Automated Vehicle Location SystemAutomated Vehicle Location System
A definition of GISA definition of GIS
GIS ( (-Geographic Information Systems)) is is a computer software, a computer software, hardware and data, and hardware and data, and personnel to help personnel to help manipulate, analyze manipulate, analyze and present information and present information that is tied to a spatial that is tied to a spatial location.location.
spatial locationspatial location–usually –usually a geographic locationa geographic location
What is GISWhat is GIS
Different layers Typically a GIS is used for
handling maps of one kind or another.
These might be represented as several different layers where each layer holds data about a particular kind of feature.
Each feature is linked to a position on the graphical image of a map
““Smart Maps”:Smart Maps”: linking database to linking database to
maps.maps.
GISGIS–One –One exampleexample with Five with Five Data LayersData Layers
Maps and Database are Maps and Database are InteractiveInteractive
Some ways of using GIS Some ways of using GIS TechnologyTechnology
Wherever Spatial Data Analysis is Wherever Spatial Data Analysis is NeededNeeded
Emergency ServicesEmergency Services – Fire & Police– Fire & Police Environmental Environmental – Monitoring & Modeling– Monitoring & Modeling BusinessBusiness – Site Location, Delivery Systems– Site Location, Delivery Systems IndustryIndustry – Transportation, Communication,– Transportation, Communication,
Mining, Pipelines, HealthcareMining, Pipelines, Healthcare Government Government – Local, State, Federal, Military– Local, State, Federal, Military EducationEducation – Research, Teaching Tool, – Research, Teaching Tool,
AdministrationAdministration
GIS ApplicationGIS Application
In the past,Survey data was first read into a computational program, where errors are eliminated and point coordinates reduced.
The reduced data is then transferred to a CAD program and complemented with construction elements
Finally the data is transferred to a central system.
GIS ApplicationApplication Today
Today’s modern systems allow data to be transferred directly to the GIS database.
All information is immediately available for further processing such as correcting errors, performing calculations, etc.
GIS ApplicationApplication Today
Handheld GIS computer system
GPS based interface
Commercial GIS data sources
Internet based data
server
Data flow For GIS ApplicationData flow For GIS Application
Data Sources for GISData Sources for GIS
Digitized and Digitized and Scanned MapsScanned Maps
– – purchased, donated, purchased, donated, free (Internet)free (Internet)
– – created by usercreated by user DataBases DataBases –Tables of –Tables of
datadata GPS GPS – Global – Global
Positioning SystemPositioning System – – accurate locationsaccurate locations
Remote Sensing &Remote Sensing & Aerial Aerial
PhotographyPhotography
Data StoreData StoreVector Formats –Vector Formats –Discrete Discrete
representations of Realityrepresentations of Reality–– give specific spatial locations explicitly–– geographic space is continuous, not quantized–– attributes are stored separately from locations
Raster Formats –Raster Formats – use square cells to use square cells to model realitymodel reality
–– Matches hardware nicely
–– Reduced spatial precision
–– Large storage requirements
Raster Data Compression
Run-length encoding Chain codes Quadtrees
Run-length Encoding
Chain Codes
QuadtreeQuadtree starts with entire map divided into quadrants. Quadtree starts with entire map divided into quadrants. Each quadrant is subdivided until it is homogeneous.Each quadrant is subdivided until it is homogeneous.
Four quadrants are: NW, NE, SW, and SEFour quadrants are: NW, NE, SW, and SE smallest unit is a grid cellsmallest unit is a grid cell
Data QueryData Query Identifying specific featuresIdentifying specific features
Identifying features based on conditions
Florida counties with a
population greater than
300,000
Data AnalysisData Analysis
Data DisplayData Display
Data OutputData Output
GIS based on many disciplines and technologies
– Geography – Cartography – Computer science – Mathematics – Statistics – Remote sensing/GPS/surveying – Telecommunications/Internet – Operations research/information science
GIS Technology: SoftwareGIS Technology: Software
GIS softwareGIS software provides the functions and tools provides the functions and tools needed to store, analyze, and display information about needed to store, analyze, and display information about places. places.
The key components of GIS softwareThe key components of GIS software are are Tools for entering and manipulating geographic Tools for entering and manipulating geographic
information such as addresses or political boundaries information such as addresses or political boundaries A database management system (DBMS) A database management system (DBMS) Tools that create intelligent digital maps you can Tools that create intelligent digital maps you can
analyze, query for more information, or print for analyze, query for more information, or print for presentation presentation
An easy-to-use graphical user interface (GUI) An easy-to-use graphical user interface (GUI)
Major GIS softwareMajor GIS software ARCGIS (ARCGIS (ArcView 8.1)ArcView 8.1)
ArcView GIS Data SetsArcView GIS Data Sets
The GIS Data set usedThe GIS Data set used Shape file Shape file
• Consisting of :Consisting of : Shape file (*.shp)Shape file (*.shp) Shape Index (*.shx)Shape Index (*.shx) Database table (*.dbf)Database table (*.dbf)
• Additional files may be present and required as Additional files may be present and required as wellwell
ArcView GIS ArcView GIS
Three Principles ModulesThree Principles Modules ArcCatalogArcCatalog ArcMapArcMap ArcToolboxArcToolbox
ArcCatalogArcCatalog
A window into your database
Browse your data Manage your data Create and view data
documentation
ArcMapArcMap Primary display
application Perform map-
based tasks Displaying Editing Querying Analyzing Charting Reporting
ArcToolboxArcToolbox
Major functions: Data management,
analysis, and conversion
Variation of tools between ArcGIS products
GIS ResourcesGIS Resources GIS InformationGIS Information University of California Berkeley, GIS libraryUniversity of California Berkeley, GIS library
http://http://sunsitesunsite..berkeleyberkeley..eduedu/GIS//GIS/gisnetgisnet.html .html Spatial Odyssey, University of Maine, GIS Literature DatabaseSpatial Odyssey, University of Maine, GIS Literature Databasehttp://http://wwwsgiwwwsgi..ursusursus..mainemaine..eduedu/ /
GIS Software SourcesGIS Software Sources Environmental Systems Research Institute, Inc. (ESRI)Environmental Systems Research Institute, Inc. (ESRI)
http://www.http://www.esriesri.com/.com/ MapInfoMapInfo
http://www.http://www.mapinfomapinfo.com/ .com/ Intergraph Intergraph
http://www.http://www.intergraphintergraph.com/.com/dynamicdefaultdynamicdefault.asp.asp AutoCADAutoCAD
http://http://usausa..autodeskautodesk.com/.com/adskadsk//servletservlet/home?/home?siteIDsiteID=123112&id=129446=123112&id=129446
Clark Labs Clark Labs http://www.clarklabs.org/http://www.clarklabs.org/
Global Positioning System Global Positioning System (GPS)(GPS)
The Global Positioning The Global Positioning System (GPS)System (GPS)
is a satellite-based navigation is a satellite-based navigation system made up of a network system made up of a network of 24 satellites placed into orbit of 24 satellites placed into orbit by the U.S.Department of by the U.S.Department of Defense.Defense.
GPS satellitesGPS satellites 24 Satellites in 6 planes, each 24 Satellites in 6 planes, each
plane has 4 satellitesplane has 4 satellites These space vehicles (SVs) These space vehicles (SVs)
send radio signals from space.send radio signals from space.
What does the GPS do
Satellite signals can be Satellite signals can be processed in a GPS receiver.processed in a GPS receiver.
GPS receiver will show your GPS receiver will show your EXACT location on the EarthEXACT location on the Earth (latitude and longitude)
Helps you find your way to a specified location
Let’s you know what direction you are heading and how fast you are going
GPS- How it worksGPS- How it works Measuring the distance from a satellite by measuring Measuring the distance from a satellite by measuring
travel time of radio signals secondstravel time of radio signals seconds
Distance = speed of light * latency in timeDistance = speed of light * latency in time Four GPS satellite signals are used to compute positions Four GPS satellite signals are used to compute positions
in three dimensions and the time offset in the receiver in three dimensions and the time offset in the receiver clock.clock.
GPS- How it worksGPS- How it works
Given 1 satellite …Given 1 satellite …
We can locate our We can locate our position on the position on the surface of a spheresurface of a sphere
GPS- How it worksGPS- How it works
Given 2 satellitesGiven 2 satellites
We can locate our We can locate our position on the position on the intersection of 2 intersection of 2 spheres (a circle)spheres (a circle)
GPS- How it worksGPS- How it works
Given 3 satellites …Given 3 satellites …
We can locate our We can locate our position on the position on the intersection of 3 intersection of 3 spheres (2 points)spheres (2 points)
GPS-How it worksGPS-How it works
Given 4 satellites …Given 4 satellites …
We can locate our position We can locate our position on the intersection of 4 on the intersection of 4 spheres (1 point). The point spheres (1 point). The point should be located on the should be located on the earth’s surfaceearth’s surface
GPS- How it worksGPS- How it works The GPS receiver compares the time a signal was The GPS receiver compares the time a signal was
transmitted by a satellite with the time it was received. transmitted by a satellite with the time it was received. The time difference tells the GPS receiver how far away The time difference tells the GPS receiver how far away the satellite is.the satellite is.
With four or more satellites in view, the receiver can With four or more satellites in view, the receiver can determine the user's 3D position (latitude, longitude and determine the user's 3D position (latitude, longitude and altitude).altitude).
Pocket Streets- an example with Pocket Streets- an example with GPS and GISGPS and GIS
Pocket Streets offers exciting Pocket Streets offers exciting
features such as street-smart features such as street-smart
mapping, map customization, mapping, map customization,
GPS and Microsoft OutlookGPS and Microsoft Outlook
integration. integration. With Pocket Streets on your With Pocket Streets on your
Pocket PC, you will take a smart Pocket PC, you will take a smart
map with you wherever you go.map with you wherever you go.
Pocket Streets- an example with Pocket Streets- an example with GPS and GISGPS and GIS
Download the map for the city.Download the map for the city.
Connect the GPS receiver to Connect the GPS receiver to
Pocket PC. Pocket PC.
Choose "Track Position" from theChoose "Track Position" from the
GPS menu to show your current GPS menu to show your current
position on the map. position on the map.
The position moves when you move.The position moves when you move.
Pocket Streets- an example with Pocket Streets- an example with GPS and GISGPS and GIS
Tap-and-Hold on either a Contact Tap-and-Hold on either a Contact with an address, or a Calendar with an address, or a Calendar appointment that has an address appointment that has an address in the location.in the location.
Choose "Find On Map" from the Choose "Find On Map" from the pop-up menu to show the location pop-up menu to show the location
in Pocket Streets.in Pocket Streets.
Pocket Streets- an example with Pocket Streets- an example with GPS and GISGPS and GIS
With GPS, you can get your With GPS, you can get your
Current Location. Current Location.
From the outlook, you get the From the outlook, you get the
Address of your contacts and GIS Address of your contacts and GIS
Will find the location on the map.Will find the location on the map.
So, Pocket Street will guide you So, Pocket Street will guide you
to your destinationto your destination
Automated Vehicle Location Automated Vehicle Location SystemSystem
Where is the bus What direction is
the bus traveling to What is the travel
speed Where is stop How long is the stop
Automated Vehicle Location Automated Vehicle Location SystemSystem
How Do GPS , GIS and AVL Relate? GPS receiver calculates its position (latitude and
longitude) and record the information at fixed time
interval GPS transmitter transmits location and vehicle
dynamic data to control center at prescribed interval Control center system process data accoding to
customer specifications GIS Software display filtered information on the screen
with map layer
Automated Vehicle Location Automated Vehicle Location SystemSystem
ConclusionsConclusions
GPS can show your EXACT location on the EarthGPS can show your EXACT location on the Earth (latitude and longitude)
GIS provides several different map layers where each layer holds data about a particular kind of feature related to spatial data.
Using GIS and GPS we can capture, management, analysis, modeling and display geographically referenced data for decision making. It is a way in which to begin to represent and model the real world.