1. INTRODUCTION TO GEOGRAPHIC INFORMATION SYSTEMS

2. GOALS Answer the question: “What is a GIS?”Answer the question: “What is a GIS?” Learn some of the basic terminology used in a GISLearn some of the basic terminology used in a GIS Become familiar with the general operations and applications of a GISBecome familiar with the general operations and applications of a GIS See some of the analyses performed in a GISSee some of the analyses performed in a GIS

3. Information Systems

4. Data vs. Information Data, by itself, differs from informationData, by itself, differs from information Data is of little use unless it is transformed into informationData is of little use unless it is transformed into information Information is an answer to a question based on raw dataInformation is an answer to a question based on raw data We transform data into information through the use of an Information SystemWe transform data into information through the use of an Information System

5. Information System

6. More than just an electronic map makerMore than just an electronic map maker More than a digital databaseMore than a digital database More than just a software packageMore than just a software package What is a GIS?

7. GIS--What is it? No easy answer! Geographic/Geospatial InformationGeographic/Geospatial Information –information about places on the earth’s surface –knowledge about “what is where when” –Geographic/geospatial: synonymous GIS--what’s in the S?GIS--what’s in the S? –Systems: the technology –Science: the concepts and theory –Studies: the societal context

8. What is a GIS? A GIS is a computer system capable of assembling, storing, manipulating/ analyzing, and displaying geographically referenced information (spatial), i.e. data identified according to their locations.A GIS is a computer system capable of assembling, storing, manipulating/ analyzing, and displaying geographically referenced information (spatial), i.e. data identified according to their locations. A decision support system involving the integration of spatially reference data in a problem solving environment.A decision support system involving the integration of spatially reference data in a problem solving environment. A GIS also includes operating personnel and the data that go into the system.A GIS also includes operating personnel and the data that go into the system.

9. Components of a GIS

10. Geographic Information System: intuitive description A map with a database behind it.A map with a database behind it. A virtual representation of the real world and its infrastructure.A virtual representation of the real world and its infrastructure. A consistent “as-built” of the real world, natural and manmadeA consistent “as-built” of the real world, natural and manmade Which is queried to support on-going operationsqueried to support on-going operations summarized to support strategic decision making and policy formulationsummarized to support strategic decision making and policy formulation analyzed to support scientific inquiryanalyzed to support scientific inquiry

11. GIS System Architecture and Components Data Input Query Input Geographic Database Output: Display and Reporting Transforma tion and Analysis

12. Knowledge Base for GIS GIS Application Area: public admin. planning geology mineral exploration forestry site selection marketing civil engineering criminal justice surveying Computer Science: graphics visualization database system administration security Geography and related: cartography geodesy photogrammetry landforms spatial statistics. The convergence of technological fields and traditional disciplines.

13. Air Photos Streets Buildings Components of a GIS GIS People Software Hardware Procedures

14. Sources of Input Data Global Positioning System (gps)Global Positioning System (gps) –a system of earth-orbiting satellites which can provide precise (100 meter to sub-cm.) location on the earth’s surface (in lat/long coordinates or equiv.) Remote SensingRemote Sensing –Use of satellites or aircrafts to capture information about the earth’s surface –Digital images a key product (map accurate digital photos)

15. Properties of Real World Geographic Information LocationLocation Attributes Spatial Relationships

16. Geographic Objects So the question arises: “How do we represent an object in space with a computer?”So the question arises: “How do we represent an object in space with a computer?” –An object is any geographically referenced entity Lake, river, road, country, sampling site, etc.Lake, river, road, country, sampling site, etc.

17. Outline for The Remaining Three steps are involved in order to go from the real world geographic object to geographic object on the computerThree steps are involved in order to go from the real world geographic object to geographic object on the computer 1.Representations of Geographic Reality 2.Linking Attributes to Geographic Representation 3.Spatial Relationships between Geographic Representations

18. 1. Representations of Geographic Reality: The Data Model Approach

19. Data Models Allows the geographic features in real world locations to be digitally represented and stored in a database so that they can be abstractly presented in map (analog) form, and can also be worked with and manipulated to address some problem Two common methods are used:Allows the geographic features in real world locations to be digitally represented and stored in a database so that they can be abstractly presented in map (analog) form, and can also be worked with and manipulated to address some problem Two common methods are used: –Vector data model –Raster data model

21. Vector Data Model Abstract spatial featuresAbstract spatial features –Point –Line –Area (polygon) Record coordinatesRecord coordinates Good for representing clearly defined objectsGood for representing clearly defined objects Spatial relationships can be definedSpatial relationships can be defined

22. Point Line Area or Polygon

23. The Vector GIS Model: examples roads hydrology topography Here we have three layers or themes: --roads, --hydrology (water), --topography (land elevation) They can be related because precise geographic coordinates are recorded for each theme. longitude latitude longitude latitude Layers are comprised of two data types Spatial data which describes location (where) Attribute data specifying what, how much, when All geographic data has 4 properties: projection, scale, accuracy and resolution

24. Raster Data Model Regular grid of cellsRegular grid of cells –Each cell represents an area on the ground –Spatial resolution Value assigned to cell represents attributeValue assigned to cell represents attribute –Land cover –Elevation Satellite imagesSatellite images Good for representing continuously changing attributesGood for representing continuously changing attributes

25. Real World Vector Representation Raster Representation Concept of Vector and Raster line polygon point

28. Street Network layer: lines Land Parcels layer: polygons Raster (image) Layer Vector Layers Projection:State Plane, North Central Texas Zone, NAD 83 Resolution:0.5 meters Accuracy:1.0 meters Scale:see scale bar 0 1500 3000 Feet

29. Overlay based on Common Geographic Location

30. Location Absolute locationsAbsolute locations –Described by coordinate system geographicgeographic projectedprojected Relative locationsRelative locations –Described through a relationship between objects.

31. a. Geographic Coordinate Systems Reference system for curved surface of earth Network of intersecting lines ( graticule) Longitude Latitude The starting point is defined at the intersection of equator and primary meridian.The starting point is defined at the intersection of equator and primary meridian.

32. b. Projected Coordinate System Reference system for features on a flat (projected) surface Cartesian coordinate system with designated origin Many different projected coordinate systems – –Ex. UTM

33. Map Projections Projection of round earth onto flat surfaceProjection of round earth onto flat surface CommonCommon –Transverse Mercator –Albers –Robinson –Planar –Conical –Cylindrical

34. 2. Linking Attributes to Geographic Representation

35. Attributes Non-spatial data associated with objectsNon-spatial data associated with objects Information about the objects in our GISInformation about the objects in our GIS –Land cover –Stream name –Flow rate –Land owner –Address Stored in tables that are linked with objectsStored in tables that are linked with objects –Polygon Attribute Table, Arc Attribute table, Point Attribute Table

36. GIS as a Database Links attribute data to spatial dataLinks attribute data to spatial data Spatially relates different objectsSpatially relates different objects –Topology Allows for spatial and attribute data queries and analysisAllows for spatial and attribute data queries and analysis

39. 3. Spatial Relationships between Geographic Representations

40. Spatial Relationships Geometric characteristics of individual objectsGeometric characteristics of individual objects –Length, area, perimeter, shape Spatial relationships between 2 or more objectsSpatial relationships between 2 or more objects –Distance, direction, topology Spatial distribution of objectsSpatial distribution of objects –How objects are distributed in space

41. Topology Topology is defined as the “spatial relationships between adjacent or neighboring features.”

42. Fundamental GIS Operations

43. i.Capture ii.Store iii.Edit iv.Analysis v.Display vi.Output

44. i. Capturing Data DatabasesDatabases GPSGPS Remote SensingRemote Sensing SensorsSensors OthersOthers

45. ii. Data Storage Through database management systemThrough database management system Links attribute to spatial informationLinks attribute to spatial information

46. iii. Data Editing Updating or correcting featuresUpdating or correcting features –shapes and attributes

47. iv. GIS Analysis “Visualizing and combining geographic data to derive new information”“Visualizing and combining geographic data to derive new information” –Overlay maps, plotting population on a map etc. QueriesQueries –attribute, location GeoprocessingGeoprocessing –Analysis of spatial relationships between objects in a layer or objects in multiple layers –create new data sets

48. Data Query Queries are used to pull information out of a GISQueries are used to pull information out of a GIS You can think of a query as a question posed to the GISYou can think of a query as a question posed to the GIS Replies with both spatial and attribute informationReplies with both spatial and attribute information

50. Geoprocessing Any GIS operation that creates new dataAny GIS operation that creates new data SimpleSimple –Copy one data set and paste it somewhere else AdvancedAdvanced –Multiple operations on multiple data sets to create new, unique features

51. Advanced Geoprocessing Data extractionData extraction –creating a subset of features from one data set based on the geographic extent of another Overlays –combination of two or more data sets to create new data set ProximityProximity –finding areas that are near features

52. v. vi. Display/Output A GIS provides the tools to display layers that allow the user to visually analyze geographic relationshipsA GIS provides the tools to display layers that allow the user to visually analyze geographic relationships Overlay different themesOverlay different themes Design a map using data layers and output in multiple formatsDesign a map using data layers and output in multiple formats

53. Why Study GIS? 80% of local government activities estimated to be geographically based80% of local government activities estimated to be geographically based –zoning, public works (streets, water supply, sewers), garbage collection, land ownership and valuation, public safety (fire and police) a significant portion of state government has a geographical componenta significant portion of state government has a geographical component –natural resource management –highways and transportation businesses use GIS for a very wide array of applicationsbusinesses use GIS for a very wide array of applications –retail site selection & customer analysis –logistics: vehicle tracking & routing –natural resource exploration (petroleum, etc.) –agriculture –civil engineering and construction Military and defenseMilitary and defense –Battlefield management –Satellite imagery interpretation scientific research employs GISscientific research employs GIS –geography, geology, botany –anthropology, sociology, economics, political science –Epidemiology, criminology

54. The major areas of GIS application Local GovernmentLocal Government –Public works/infrastructure management (roads, water, sewer) –Planning and environmental management –property records and appraisal Real Estate and MarketingReal Estate and Marketing –Retail site selection, site evaluation Public safety and defensePublic safety and defense –Crime analysis, fire prevention, emergency management, military/defense Natural resource exploration/extractionNatural resource exploration/extraction –Petroleum, minerals, quarrying TransportationTransportation –Airline route planning, transportation planning/modeling Public health and epidemiologyPublic health and epidemiology The Geospatial IndustryThe Geospatial Industry –Data /application development, programming

55. Examples of Applied GIS Urban Planning, Management & PolicyUrban Planning, Management & Policy –Zoning, subdivision planning –Land acquisition –Economic development –Housing renovation programs –Emergency response –Crime analysis –Tax assessment Environmental SciencesEnvironmental Sciences –Monitoring environmental risk –Modeling storm water runoff –Management of watersheds, floodplains, wetlands, forests, aquifers –Environmental Impact Analysis –Groundwater modeling and contamination tracking Political SciencePolitical Science –Redistricting –Analysis of election results –Predictive modeling Civil Engineering/Utility –Locating underground facilities –Designing alignment for freeways, transit –Coordination of infrastructure maintenance Business –Demographic Analysis –Market Penetration/ Share Analysis –Site Selection Education Administration – Attendance Area Maintenance – Enrollment Projections – School Bus Routing Real Estate –Neighborhood land prices –Traffic Impact Analysis –Determination of Highest and Best Use Health Care –Epidemiology – Needs Analysis – Service Inventory

56. Summary A GIS combinesA GIS combines –Spatial and attribute database –Processing tools –Graphic Capabilities –Users Create a system of advanced spatial analysis for multiple usesCreate a system of advanced spatial analysis for multiple uses Questions?Questions?