1. Karl Hennermann School of Environment and Development Session 2: What you absolutely need to know about spatial data Geographic Information Systems

2. Contents I.Defining GIS II.The world is a set of layers III.Vectors and rasters – representing real world features IV.Where am I? Coordinate systems V.Making maps: cartographic projections VI.Challenges and constraints for GIS VII.Q&A Karl Hennermann, 13-03-2013

3. Contents I.Defining GIS II.The world is a set of layers III.Vectors and rasters – representing real world features IV.Where am I? Coordinate systems V.Making maps: cartographic projections VI.Challenges and constraints for GIS VII.Q&A Karl Hennermann, 13-03-2013

4. Defining GIS GIS is not a software product. Karl Hennermann, 13-03-2013

5. Definition I: GIS is… A computer system capable of holding and using data on geographical objects ESRI (1997): Understanding GIS. The ARC/INFO method. Karl Hennermann, 13-03-2013

6. “... geographical objects” Karl Hennermann, 13-03-2013

7. “...data on geographical objects” Location, location, location Karl Hennermann, 13-03-2013

8. “...data on geographical objects” School locations (-324072;1667468), (322317;1665019), (-321993;1661876), (-323010;1660028), (-324211;1659751), (-324396;1660305) Flooded area Karl Hennermann, 13-03-2013

9. Definition I: GIS is… A computer system capable of holding and using data on geographical objects ESRI (1997): Understanding GIS. The ARC/INFO method. Karl Hennermann, 13-03-2013

10. Definition II: GIS is… An organised collection of computer hardware, software, geographical data, and personnel designed to efficiently capture, store, update, manipulate, analyse, and display all forms of spatially referenced information. ESRI (1997): Understanding GIS. The ARC/INFO method. Karl Hennermann, 13-03-2013

11. “...hardware, software, geographical data, and personnel to capture, store, update, manipulate, analyse, and display...“ Process view Data CollectionPre-processingData Storage & ManagementAnalysisProduct Generation (maps, reports) Architecture view Hardware Software Geospatial data Personnel & Skills Karl Hennermann, 13-03-2013

12. So, what is GIS about? GIS is not a software product. GIS is about the methods / techniques of analysing data spatially or geographically You do not have to use GIS software for work to count as geographical analysis The software simply allows these methods to be carried out efficiently Karl Hennermann, 13-03-2013

13. Contents I.Defining GIS II.The world is a set of layers III.Describing the real world - vectors and rasters IV.Where am I? Coordinate systems V.Making maps: cartographic projections VI.Challenges and constraints for GIS VII.Q&A Karl Hennermann, 13-03-2013

14. The world is a set of layers Karl Hennermann, 13-03-2013 Jones, Christopher (1997): Geographical Information Systems and Computer Cartography. Addison Wesley Longman.p30

15. Contents I.Defining GIS II.The world is a set of layers III.Describing the real world - vectors and rasters IV.Where am I? Coordinate systems V.Making maps: cartographic projections VI.Challenges and constraints for GIS VII.Q&A Karl Hennermann, 13-03-2013

16. Describing the real world - vectors Karl Hennermann, 13-03-2013 File Image (c) Google 14 15 34 85 3 17 22 18 44

17. Describing the real world - vectors Karl Hennermann, 13-03-2013 Image (c) Google Bus stops (Point) Land use (Polygon) Roads (Polyline)

18. Describing the real world - rasters Karl Hennermann, 13-03-2013 Logical Data Model 1: Green space 2: Water body 3: Residential 4: Industrial 5:... 32 512125 5317265 100 1,1,1,1,1,1,2,1,1,1, 1,1,4,4,1,1,2,1,1,1, 4,4,4,4,1,2,1,1,1,1, 4,1,1,1,2,1,3,1,1,1, 4,4,4,2,1,3,3,3,1,1, 3,3,4,2,1,3,3,3,3,1, 3,3,2,4,4,3,3,3,3,3, 3,2,4,4,4,3,3,3,3,3, 2,4,4,4,4,3,3,3,3,3, EOF File Image (c) Google

19. Contents I.Defining GIS II.The world is a set of layers III.Describing the real world - vectors and rasters IV.Where am I? Coordinate systems V.Making maps: cartographic projections VI.Challenges and constraints for GIS VII.Q&A Karl Hennermann, 13-03-2013

20. Geographic Coordinate Systems (use on spheres and with GPS) Karl Hennermann, 13-03-2013 The most common geographic coordinate system is: Decimal Degrees on WGS 1984 In the UK also Decimal Degrees on OSGB 1936 The Geodetic Datum The Measurement Units (almost always DD)

21. Contents I.Defining GIS II.The world is a set of layers III.Describing the real world - vectors and rasters IV.Where am I? Coordinate systems V.Making maps: cartographic projections VI.Challenges and constraints for GIS VII.Q&A Karl Hennermann, 13-03-2013

22. Making maps: cartographic projections Karl Hennermann, 13-03-2013 A method by which the curved surface of the earth is portrayed on a flat surface. This generally requires a systematic mathematical transformation of the earth's graticule of lines of longitude and latitude onto a plane. ESRI (2010): ArcGIS Desktop Glossary

23. Making maps: cartographic projections Karl Hennermann, 13-03-2013 + + + + + Transverse Mercator

24. Making maps: cartographic projections Karl Hennermann, 13-03-2013 Snyder, John P. (1987), Map Projections – A Working Manual. U.S. Geological Survey Professional Paper 1395. Washington. The Transverse Mercator projection

25. Making maps: cartographic projections Karl Hennermann, 13-03-2013 There are hundreds of geographic coordinate systems, projections, and projected coordinate systems. Always know what the coordinate system and projection of your data is. How to make the British National Grid: Take a spheroid with the OSGB 1936 spec and project it with Transverse Mercator, using the Greenwich meridian as Central Meridian. Then overlay a projected coordinate system, measuring in meters North and East from the Isles of Scilly.

26. 4 11 000 4 12 000 4 13 000 Projected Coordinate Systems (use on maps) Karl Hennermann, 13-03-2013 British National Grid: Units: meters Reference point is SW of Isles of Scilly Northing: 4 09 000 (meters north of the reference point) Easting: 4 11 000 (meters east of the reference point) 1000m 4 08 000 4 09 000

27. Contents I.Defining GIS II.The world is a set of layers III.Describing the real world - vectors and rasters IV.Where am I? Coordinate systems V.Making maps: cartographic projections VI.Challenges and constraints for GIS VII.Q&A Karl Hennermann, 13-03-2013

28. Challenges and constraints Data Cost, arguing that it pays off, and defining business processes Multiplication of effort, Interoperability, SDIs III.Challenges and Constraints Karl Hennermann, 13-03-2013

29. Further reading Paul Longley, Mike Goodchild, David Maguire, David W. Rhind (2010): Geographic Information Systems and Science. 3 rd Ed. John Wiley & Sons Ian Heywood, Sarah Cornelius, Steve Carver (2011): An Introduction to Geographical Information Systems. 4 th Ed., Prentice Hall Karl Hennermann, 13-03-2013

30. Thank you Karl Hennermann, 13-03-2013

31. Q&A Karl Hennermann, 13-03-2013