Introduction to Geographic Information Systems

2. The Objectives of this Topic Understand the nature of GIS as an information technology paradigm. Understand the basic methods of information analysis in a GIS. Investigate application domains of GIS with a set of examples.

3. Information Technology and Geography 1. What is Information? 2. What is Geographical Information? 3. What are Geographic Information Systems?

4. What is Information? Information Knowledge about something. Recorded in some way. Information age The computer has become the main mean of storing and accessing information. Tremendous amounts of digital information created: Spreadsheets. Databases. Internet. Most of the �interesting� jobs involve information processing.

5. What is Information?

6. What is Information? Information Systems Dominant tool. Set of computer programs that are used to input (encode) information and store it in a structured manner. Can be retrieved, analyzed and, finally, reported as a table, graph, map or picture.

7. What is Information? �Knowledge is power� Having information offers a way to control the parameters of our environment. Making decisions (resource allocation). With perfect information, one should be able to make optimal decisions. Impossible to be perfectly informed, so decisions are always imperfect (sub-optimal).

8. What is Geographical Information? Spatial information Between 70 and 80% of the digital information is spatially related. Can be placed on a map. Tools to deal with this information are consequently very useful. Reveal information that was previously �hidden�.

9. A Taxonomy of Information

10. What is Geographical Information? Spatially related Can be assigned coordinates or any spatial reference. On the surface of the earth. Involves location and organization. Scale Can be from general to specific. Simple to complex. A satellite can generate one terabyte (1012 bytes) of information per day. Dynamics Spatial dynamics (variations in space). Temporal dynamics (variations in time).

11. The Purpose of GIS 1. What is a GIS? 2. History of GIS 3. General Purpose

12. What is a GIS? Geographic Information System Form of Information System applied to geographical data. Produce information which will be useful in decision-making. Managing use of land, resources, transportation, retailing, oceans or any spatially distributed entities. Connection between the elements of the system is geography, e.g. location, proximity, spatial distribution. System of hardware, software and procedures Support the capture, management, manipulation, analysis, modeling and display of spatially-referenced data. Solving complex planning and management problems.

13. What is a GIS? Information Systems Information system specializing in the input, storage, manipulation, analysis and reporting of geographical (spatially related) information.

14. Basic Structure of a GIS

15. What is a GIS?

16. Representation of Geographical Information in a GIS

17. History of GIS Prior to 1960 GIS�s origins lie in thematic cartography. Many planners used the method of map overlay using manual techniques. The 1960s and 1970s Many new forms of geographic data and mapping software. First GIS developed in Canada for land use inventory. Development of the first computer cartography packages for mainframe computers. First remote sensing images. Mathematical Models.

18. History of GIS The 1980s and 1990s First commercial GIS Packages. Diffusion of Microcomputers. Integration with other software (mainly CAD and databases). US Census Bureau efforts in the 1980s: Digitize spatial, economic and demographic attributes of the United States. Creation of the TIGER format (Topologically Integrated Geographic Encoding and Reference ). The 2000s Integrated Information technologies with geography. Powerful applications on desktop computers. Web/network based data sources. Portable and inexpensive field GISs with GPS capabilities.

19. General Purpose GIS is a database application All information in a GIS is linked to a spatial reference. Other databases may contain locational information (street addresses, zip codes, etc.). GIS database uses geo-references as the primary means of storing and accessing information.

20. General Purpose GIS is a tool Must serve a purpose. Not an end in itself but a mean (process) to achieve this end. Should be viewed as a process rather than as software or hardware. For decision-thinking (scenarios) and decision-making (strategies). 75% of the time used to be spent at building the spatial database: Acquiring data for a new GIS has become much simpler.

21. General Purpose Advantage Ability to integrate vast quantities of spatial information. Provide a powerful repertoire of analytical tools to explore this data. Ability to separate information in layers: Combine it with other layers of information. Good employment opportunities (information society). Disadvantage Long process of encoding and verifying the integrity of information. Compatibility between different GIS (less an issue). Technology changes rapidly. Information overload.

22. General Purpose GIS as an Integrating Technology Evolved by linking a number of discrete technologies: A whole that is greater than the sum of its parts. Integrate geographical data and methods: Support traditional forms of geographical analysis. Map overlay analysis. Thematic mapping. New types of analysis and modeling: Beyond the capability of manual methods. Possible to map, model, query, and analyze large quantities of data all held together within a single database. Integrates people, data, hardware and software.

23. General Purpose People Map user: end consumer. Cartographer: producer of the end product of a GIS. Analyst: applies methods to solve geographical problems. Database administrator: build, update and administer databases. Data Remote sensing images or aerial photographs. Topographic maps. Land records. Etc.

24. General Purpose The GIS Job Market About 500,000 GIS users in the United States (another 500,000 for the rest of the world). 10% (50,000) are using GIS full-time. 15% growth each year. 75,000 people a year receive GIS training. Shortfall in training and advanced degrees. High demands to integrate GIS in all levels of the educational system.

25. Organization of Information in a GIS 1. Features 2. Attributes 3. Themes

26. Features Features Real world objects. Natural or man-made. Represented on a map as a single entity. Each map feature has a location, shape, and symbol that represents one or more of its characteristics. Points Points represent objects that have discrete locations and are too small to be depicted as areas. Schools, traffic lights, crime locations, and park benches are examples of point features.

27. Features Lines Lines represent objects that have length but are too narrow to be depicted as areas. Freeways, streets, pipelines, and waterways are examples of line features. Polygons Polygons represent objects too large to be depicted as points or lines. Parks, census tracts, postal codes, and trade areas are examples of polygon (or area) features.

28. Features in ArcView

29. Attributes Attributes Features are stored in a database along with information describing them. The descriptive information stored with a feature. Attributes of a street might include its name, street type, length, street code, number of lanes, and pavement type. The attributes of a park may be its name, area, hours of operation, and maintenance schedule.

30. Attributes Relationships Features and their attributes are linked. Types: One feature as one record in a database. Many features to one record. Access the attributes for any feature or locate any feature from its attributes. Attributes are displayed in a spreadsheet-like ArcView document called a Table.

31. Attributes

32. Themes Themes A GIS links sets of features and their attributes and manages them together in units called themes. Consists of a collection of geographic features. Roads, rivers, parcels, wildlife sightings, schools, or parks. Attributes for those features. Thematic map A map (set of features) which visually represents a set of data (attributes) is called a thematic map.

33. Themes

34. Applications 1. Strengths and Pitfalls 2. Application Areas

35. Strengths and Pitfalls Possibility Organize spatially related information. Derive new information from existing information. Present the information in a graphical format (charts and maps). Assist in building scenarios. Impossibility Increase the quality of the available information. Create information. Make decisions for you.

36. Application Areas Natural Resources Management Wildlife habitat. Recreational resources. Floodplains and Wetlands. Agricultural lands. Aquifers. Forests and woodcutting. Facilities Management Transportation systems. Locating underground pipes and cables. Loads in electrical networks and tracking energy use. Planning facility maintenance.

37. Application Areas Land Management Zoning and subdivision planning. Land acquisition. Environmental impact policy. Water quality management. Maintenance of ownership. Location Analysis Commercial and industrial location. Spatial marketing (stores, warehouses and competitors). Location analysis or site selection for services. Development of evacuation plans.

38. Application Areas Public services Emergencies: Vehicle routing (police, fire, ambulance). Location of medical facilities. Spatial crime statistics. Location of water sources (hydrants). Location of chemical and hazard materials. Education Research. Teaching Tool. Administration.