Introduction to Geographic Information Systems

1. Introduction to Geographic Information Systems Dr. Larry Teeter

3. What is a GIS?

4. One of a Set Geospatial technologies are technolo-gies for collecting and dealing with geographic information. There are three main types: Global Positioning Systems Remote Sensing Geographic Information Systems

5. Defining GIS • Different definitions of a GIS have evolved in different areas and disciplines • All GIS definitions recognize that spatial data are unique because they are linked to maps • A GIS at least consists of a database, map information, and a computer-based link between them

6. Definition 1: Dueker’s Feature Model "A geographic information system is a special case of information systems where the database consists of observations on spatially distributed features, activities or events, which are definable in space as points, lines, or areas. A geographic information system manipulates data about these points, lines, and areas to retrieve data for ad hoc queries and analyses" (Dueker, 1979, p 106).

7. Definition 2: A GIS is an information system "An information system that is designed to work with data referenced by spatial or geographic coordinates. In other words, a GIS is both a database system with specific capabilities for spatially-referenced data, as well as a set of operations for working with the data" (Star and Estes, 1990, p. 2).

8. Definition 3: Paul Bolstad’s Definition(author of class text) “a computer-based system to aid in the collection, maintenance, storage, analysis, output, and distribution of spatial data and information”

9. Definition 4: GIS is a multi-billion dollar business. “The growth of GIS has been a marketing phenomenon of amazing breadth and depth and will remain so for many years to come. Clearly, GIS will integrate its way into our everyday life to such an extent that it will soon be impossible to imagine how we functioned before”

10. We usually understand GIS to be computer-facilitated system • GIS is NOT only software/hardware • Also includes: • Trained personnel • Supporting Institution • Protocols for use

11. Why Learn GIS?..... Because GIS is Everywhere

12. Why computerize manual methods? • To bring together data from multiple sources (synthesis) • Analytical power • measure distance, density, area • overlay and buffer • adjacency and proximity • vicinity (neighborhood) • networks • intervisibility • Flexibility • Output Quality

13. Why GIS? • Resource depletion/degradation • Increased problem complexity • Demands by the body politic • Improved capabilities • Increased competition

14. Why GIS? • Expanded capabilities - do the heretofore impossible • Improved efficiency - reduce speed of analysis 10-fold or more

15. Why GIS? Traffic Information

16. Monitoring and Mapping Sea Ice in near Real Time

17. Why GIS? Pavement quality inventory and monitoring

18. Why GIS? Sustaining Lobster Fisheries in Penobscot Bay Why is it important? Fisheries stocks dwindling, lobster an economic mainstay with sustainable harvests

19. From Observations and Process Knowledge to Prediction and Action

20. Where did GIS come from? • GIS is built upon knowledge from geography, cartography, computer science and mathematics • Geographic Information Science is a new interdisciplinary field built out of the use and theory of GIS

21. Basic Concepts of a GIS - spatial data from different data sources are registered to same scale to form data planes (layers) - These data are used together (overlaid) to produce a variety of derived information - data layers resource manager might use: land ownership transportation networks right of way utilities land use vegetation cover surface water endangered species elevation soil type jurisdictional boundaries pest & disease

22. Questions a user might ask of a GIS: • -Where is object A (RCW cavity trees)? • -Where is A in relation to place B? • -How many occurrences of type A are within distance X of B? • -What is the value of function Z (distance from parking area) at position X?-How large is B (campground area, perimeter)

23. A Brief History of GIS • GIS’s origins lie in thematic cartography • Many planners used the method of map overlay using manual techniques • Manual map overlay as a method was first described comprehensively by Jacqueline Tyrwhitt in a 1950 planning textbook • McHarg used blacked out transparent overlays for site selection in Design with Nature

24. A Brief History of GIS (cont.) • The 1960s saw many new forms of geographic data and mapping software • Computer cartography developed the first basic GIS concepts during the late 1950s and 1960s • Linked software modules, rather than stand-alone programs, preceded GISs

25. A Brief History of GIS (cont.) • Computerized GIS began in mid - 60's - CGIS - 1964 - MLMIS - 1969 - FRIS - early 70's - required mainframe computers - mini computers made technology more accessible (early 80's)

26. A Brief History of GIS (cont.) • GIS was significantly altered by (1) the PC and (2) the workstation • During the 1980s, new GIS software could better exploit more advanced hardware • User Interface developments led to GIS's vastly improved ease of use during the 1990s • During the 1980s, new GIS software could better exploit more advanced hardware

27. Features as Objects • The standard feature model divides a mapped landscape up into features, that can be points, lines, or areas. • Almost all human activity and natural phenomena are spatially distributed, so can be studied using a GIS. • A GIS uses map features to manage data.