1. Concepts and Functions of Geographic Information Systems (5/5) MSc GIS - Alexander Mogollon Diaz Department of Agronomy 2009

2. Concepts and Functions of GIS .PPT Topic #1 Topic #2 Topic #3 1 A GIS is an information system GIS is a technology 2 Spatial Data modelling Sources of data for geodatasets Metadata 3 Geo-referencing Coordinate transformations 4 Database management 5 Spatial Analysis

3. Functionalities of GIS INPUT QUERY - DISPLAY - MAP ANALYSE STRUCTURE MANAGE TRANSFORM

5. Spatial analysis tools

8. Raster topology Column-/row-number of cells implicitly contains topological information

11. 1. Generalisation of lines; of polygons

12. A A DISSOLVE polygons = dropping boundary lines using topological info

15. Topological overlay

16. Topological Overlay Poly-on-Poly

17. Topological overlay line-node, poly-line, left-right is modified

18. Topological overlay and Boolean logic Intersection Union Subtraction Union without intersection Applied to overlapping polygons and/or lines

19. Topological overlay

20. Topological Overlay Line-in-Poly

21. Topological Overlay Point (node)-in-Poly Half-line algorithm: At uneven # intersections, Point is in last-left polygon

23. Buffering: Steps A & B TARGET

24. Buffering: Steps A & B TARGET

28. Networks

29. Topological networks 10

30. Finding paths

32. Distances in raster-geodatasets

33. 1. Buffering - Raster TARGET = cell or group of cells BUFFERING = selection of cells which match the distance threshold. Result = WINDOW Operations can be performed on the window, e.g. FILTERING

34. 2. Example: Majority filter 5 * 5 The most frequent class in each (moving, e.g. 5*5) window is atributed to the central cell

37. 3. Map Algebra

38. 4. Cost-Distance analysis using a ‘friction’ surface or friction-geodataset Friction surface

39. 4. Cost-Distance analysis (1/v in min/km) (min; resolution = 1 km)

41. Questions or remarks ? Thank you …