GEOG5870: Web-based GIS Lecture 1

1. GEOG5870: Web-based GISLecture 1 Oliver Duke-Williams o.w.duke-williams@leeds.ac.uk

2. Week 1 Introduction • Introduction to module • Module structure, timetable and assessment • Web-based GIS • What do we mean by this? • What types of web-based GIS are there? • Week 1 Practical • Discussion of this week’s practical task

3. Module structure • Blended course of face-to-face and on-line materials • Weekly practical classes • Assessment for the course is based on assessed course work

4. Lecture timetable • Three weekly cycle: • Week a: Face-to-face lecture • Week b: On-line lecture • Week c: On-line lecture • Each week will be accompanied with a practical class

5. Assessed work • The mark for the course will be based on a web-based map application produced by the student, accompanied by description of how it was produced.

6. Module outline • Introduction • What is ‘web-based GIS’? • Types of web maps and web GIS • OGC Web Map Servers • Google Maps • Basic and advanced use • Mapserver • Server based map applications • Local and remote data sources • Databases and spatial data • Assessed work • Planning and constructing your assessed work

8. Web-based GIS • What is ‘web-based GIS’? • Types of web-based GIS • Differences between web-based and other GIS • Growth in power of web-based GIS • Web Map Servers and Web Feature Servers

9. Does not require specialized client software However, web browsers are a heterogeneous platform Use of Javascript Use of Java Use of plugins Differing degrees of support for different graphics formats etc. Growing platform variety What is “web-based GIS” A map-based system that is delivered via a web browser “web-based GIS”

10. SVG example www.statistics.gov.uk/populationestimates/svg_pyramid/uk/index.html

11. GIS and the mobile web • Mobile web platforms have additional advantages and disadvantages • Small screen size • Constrained user input • Readily available location • Location based services

12. Does not require specialized client software However, web browsers are a heterogeneous platform Use of Javascript Use of Java Use of plugins Differing degrees of support for different graphics formats etc. Growing platform variety What is “web-based GIS”? A map-based system that is delivered via a web browser “web-based GIS” • Some degree of interactivity above and beyond a simple static map • That interactivity may be closely or weakly coupled with the map • A ‘true’ GIS might include • Analysis functions • Control over display of layers

13. Map data on the web Web mapping Web GIS Web cartography

14. Types of web GIS • What types of web-based GIS are there? • How might we classify them? • Examples • Classification attempts

15. Google Maps

16. Google Maps

17. Google Maps

18. Google Maps

19. Google Maps www.casa.ucl.ac.uk/googlemaps/OAC-super-EngScotWales.html

20. Google Maps

22. More examples - transport

23. TrafficMap www.trafficmap.co.uk

25. ‘Jamcams’ www.bbc.co.uk/london/jamcams_interactive_map.shtml

28. Weather maps www.usatoday.com/weather

29. www.snow-forecast.com

30. Physical phenomena earthquakes.tafoni.net

31. Classification • Peng (2001) and Campagna and Delano (2004) has studied the use of Public Participation GIS (PPGIS) over the Internet, and have separately suggested some useful classificatory terms

32. Peng, 2001 • Peng describes a framework for classifying web-based public participation systems (WPPS) • Development of internet GIS • Internet as a way to disseminate digital data • Linking existing GIS programs to the web to offer simple functionality • Distributed components offering rich environment • System requirements • Exploration • Evaluation • Scenario building • Forum • WPPS enhances but does not replace traditional decision making processes

33. Functions and features: Peng • Internet based and platform neutral • Distributed database management • Map-based coupled with HTML based interface • Analysis models should be supported • Multiple communication channels • Proper system to support voting and expressing preferences • Highly scalable • Compatible with current standards

34. Increasing technical sophistication Content types Campagna and Delano • Adapted Peng’s taxonomy • Produced a Content / Technology matrix to assess public administration sites in Italy

35. Content / Technology Matrix

36. Content examples • C1: General information • Tourist maps • Other location maps • C2: Environment and planning • Local planning applications • Submitted map documents • C3: Raw data • Raw data for users to download • C4: Analysis tools

37. Technology examples • T1: Static maps • Embedded images in HTML or PDF documents • T2: Interactive maps • May be integrated into the site or via a link to a 3rd party such as Multimap • T3: Interactive dynamic maps • Features may include multimedia and 3D representation • T4: Interactive map based search • Query and analysis – basic web GIS functions • T5: Web-GIS advanced functions • Planning & Support Systems

38. CTM surfaces for Italy From: Campagna & Delano (2004)

39. CTM surfaces for Denmark From: Arleth (2005)

40. CTM surface for Ireland From: de Róiste (2006)

42. Web-based GIS • What is ‘web-based GIS’? • Types of web-based GIS • Differences between web-based and other GIS • Growth in power of web-based GIS • Web Map Servers and Web Feature Servers

43. Differences • What are the differences between ‘web-based’ and desktop GIS? • Universality of interface • Very limited interface components on the web • Limited access to locally stored data • Limitless remote data • Processing in browser is limited • Potential of significant server-side processing power

44. Growth in power of web-based GIS • Recent years have seen the introduction of powerful and easy to use map based tools • Introduction of GoogleMaps is the key event in this change • These have further blurred the distinction between web-mapping and web-GIS • Dangers in the ubiquity of GoogleMaps

45. Onwards from Google • GoogleMaps and similar services allow users to generate map outputs using: • Map base data from Google • Projections defined by Google • Potential to use additional data in conjunction • More sophisticated services can draw from a wider range of source data • Different map bases • Different projections • In order to make sense of multiple sources, standards are required

46. OGC Standards • Open Geospatial Consortium control various important specifications • Services • Web Map Service (WMS) • Web Feature Service (WFS) • Web Coverage Service (WCS) • Data formats and standards • Simple Features for SQL (SFS) • Geographic Markup Language (GML) • www.opengeospatial.org

47. OGC Services • Use web protocols to send and receive information • Return data plus metadata • WFS – returns linear data about features • WCS – returns raster data • WMS – returns formatted graphical rendering of a map • Use web protocols to communicate between server and client

48. Alternate data sources • Data projected for region of interest • Privately collected data • Ad hoc data

49. OpenStreetMap www.openstreetmap.org

50. OpenStreetMap www.openstreetmap.org