Presentation on theme: "An Introduction to GIS and GPS Technology"— Presentation transcript:
1 An Introduction to GIS and GPS Technology Bo ShenMarch 5, 2004
2 Overview What is GIS? GIS Application GIS Data GIS Technology(ArcGIS) What is GPS?What does the GPS do?How it worksApplication with GIS and GPSPocket StreetAutomated Vehicle Location System
3 A definition of GISGIS (-Geographic Information Systems) is a computer software, hardware and data, and personnel to help manipulate, analyze and present information that is tied to a spatial location.spatial location–usually a geographic location
4 What is GIS Different layers “Smart Maps”: linking database to maps. 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”:linking database to maps.
7 Some ways of using GIS Technology Wherever Spatial Data Analysis is NeededEmergency Services – Fire & PoliceEnvironmental – Monitoring & ModelingBusiness – Site Location, Delivery SystemsIndustry – Transportation, Communication,Mining, Pipelines, HealthcareGovernment – Local, State, Federal, MilitaryEducation – Research, Teaching Tool, Administration
8 GIS 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 elementsFinally the data is transferred to a central system.
9 GIS Application TodayToday’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.
10 GIS Application Today Handheld GIS computer system GPS based interface Commercial GIS data sourcesInternet based dataserver
12 Data Sources for GIS Digitized and Scanned Maps – purchased, donated, free (Internet)– created by userDataBases –Tables of dataGPS – Global Positioning System– accurate locationsRemote Sensing &Aerial Photography
13 Data Store Raster Formats – use square cells to model reality Vector Formats –Discrete representations of Reality– give specific spatial locations explicitly– geographic space is continuous, not quantized– attributes are stored separately from locationsRaster Formats – use square cells to model reality– Matches hardware nicely– Reduced spatial precision– Large storage requirements
14 Raster Data Compression Run-length encodingChain codesQuadtrees
22 GIS based on many disciplines and technologies – Geography– Cartography– Computer science– Mathematics– Statistics– Remote sensing/GPS/surveying– Telecommunications/Internet– Operations research/information science
23 GIS Technology: Software GIS software provides the functions and tools needed to store, analyze, and display information about places.The key components of GIS software areTools for entering and manipulating geographic information such as addresses or political boundariesA database management system (DBMS)Tools that create intelligent digital maps you can analyze, query for more information, or print for presentationAn easy-to-use graphical user interface (GUI)Major GIS softwareARCGIS (ArcView 8.1)
24 ArcView GIS Data Sets The GIS Data set used Shape file Consisting of : Shape file (*.shp)Shape Index (*.shx)Database table (*.dbf)Additional files may be present and required as well
28 ArcToolbox Major functions: Data management, analysis, and conversion Variation of tools between ArcGIS products
29 GIS Resources GIS Information GIS Software Sources University of California Berkeley, GIS library Spatial Odyssey, University of Maine, GIS Literature DatabaseGIS Software SourcesEnvironmental Systems Research Institute, Inc. (ESRI)MapInfoIntergraphAutoCADClark Labs
30 Global Positioning System (GPS) The Global Positioning System (GPS)is a satellite-based navigation system made up of a network of 24 satellites placed into orbit by the U.S.Department of Defense.GPS satellites24 Satellites in 6 planes, each plane has 4 satellitesThese space vehicles (SVs) send radio signals from space.
31 What does the GPS doSatellite signals can be processed in a GPS receiver.GPS receiver will show your EXACT location on the Earth (latitude and longitude)Helps you find your way to a specified locationLet’s you know what direction you are heading and how fast you are going
32 GPS- How it worksMeasuring the distance from a satellite by measuring travel time of radio signals secondsDistance = speed of light * latency in timeFour GPS satellite signals are used to compute positions in three dimensions and the time offset in the receiver clock.
33 GPS- How it works Given 1 satellite … We can locate our position on the surface of a sphere
34 GPS- How it works Given 2 satellites We can locate our position on the intersection of 2 spheres (a circle)
35 GPS- How it works Given 3 satellites … We can locate our position on the intersection of 3 spheres (2 points)
36 GPS-How it works Given 4 satellites … We can locate our position on the intersection of 4 spheres (1 point). The point should be located on the earth’s surface
37 GPS- How it worksThe GPS receiver compares the time a signal was transmitted by a satellite with the time it was received. The time difference tells the GPS receiver how far away the satellite is.With four or more satellites in view, the receiver can determine the user's 3D position (latitude, longitude and altitude).
38 Pocket Streets- an example with GPS and GIS Pocket Streets offers excitingfeatures such as street-smartmapping, map customization,GPS and Microsoft Outlookintegration.With Pocket Streets on yourPocket PC, you will take a smartmap with you wherever you go.
39 Pocket Streets- an example with GPS and GIS Download the map for the city.Connect the GPS receiver toPocket PC.Choose "Track Position" from theGPS menu to show your currentposition on the map.The position moves when you move.
40 Pocket Streets- an example with GPS and GIS Tap-and-Hold on either a Contact with an address, or a Calendar appointment that has an address in the location.Choose "Find On Map" from the pop-up menu to show the location in Pocket Streets.
41 Pocket Streets- an example with GPS and GIS With GPS, you can get yourCurrent Location.From the outlook, you get theAddress of your contacts and GISWill find the location on the map.So, Pocket Street will guide youto your destination
42 Automated Vehicle Location System Where is the busWhat direction isthe bus traveling toWhat is the travelspeedWhere is stopHow long is the stop
43 Automated Vehicle Location System How Do GPS , GIS and AVL Relate?GPS receiver calculates its position (latitude andlongitude) and record the information at fixed timeintervalGPS transmitter transmits location and vehicledynamic data to control center at prescribed intervalControl center system process data accoding to customer specificationsGIS Software display filtered information on the screen with map layer
45 ConclusionsGPS 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.