1. Joerg Steinruecken 17.11.09 A Web Service to personalise Map Colouring Joerg Steinruecken Department of Geoinformation Institute of Geodesy and Geoinformation University of Bonn

2. Joerg Steinruecken 17.11.09 A Web Service to personalise Map Colouring 2 Motivation World Wide Web offers geospatial data from many different sources „Mapping on Demand“: Creating maps –in real time –by combining data from different sources –for individual purposes –independent of time and place Problems: –Portrayal of data from different sources conflict

3. Joerg Steinruecken 17.11.09 A Web Service to personalise Map Colouring 3 Personalisierung Befragung Tour 1 Tour 2 Tour 4 Tour 5 Tour 6 Tour 7 Tour 3 Legend

4. Joerg Steinruecken 17.11.09 A Web Service to personalise Map Colouring 4 Motivation World Wide Web offers geospatial data from many different sources „Mapping on Demand“: Creating maps –in real time –by combining data from different sources –for individual purposes –independent of time and place Problems: –Portrayal of data from different sources conflict –Perceptibility is influenced by Users‘ visual system (colour vision impairment) Outer effects –Device specific colour reproduction –Environment (e.g. dark room or sunlight)

5. Joerg Steinruecken 17.11.09 A Web Service to personalise Map Colouring 5 Stating the problem Given –Background: Topographical Map which has a fixed graphical representation –Overlay: Objects O 1 … O n which can be portrayed by users Searching portrayal options of objects O 1 … O n Postulations –Conciseness: Visual distinguishability of objects O 1 … O n among each other of objects O 1 … O n from the topographic map for all users and on all devices –Solution „on demand“ –Access without technical barriers

6. Joerg Steinruecken 17.11.09 A Web Service to personalise Map Colouring 6 Outer Frame Service-oriented architecture Geospatial data provided by standardised services –Open Geospatial Consortium (OGC) Web Map Service (WMS) Specification –OGC Symbology Encoding (SE) / Styled Layer Descriptor (SLD) Specification

7. Joerg Steinruecken 17.11.09 A Web Service to personalise Map Colouring 7 Statement Portrayal –Options: Visual variables –Most important variable: Colour –Problem of distinguishability is reduced to the identification of well distinguishable colours –Colours are adjusted to a specific user and his device Colours provided by a Web Service

8. Joerg Steinruecken 17.11.09 A Web Service to personalise Map Colouring 8 Stating the problem with colours Given –Background: Topographical Map which contains m colours –Overlay: Objects O 1 … O n which can be portrayed by users Searching n colours for objects O 1 … O n Postulations –Conciseness: Visual distinguishability of colours of objects O 1 … O n among each other of colours of objects O 1 … O n from the colours of the topographic map for all users and on all devices –Solution „on demand“ –Access without technical barriers

9. Joerg Steinruecken 17.11.09 A Web Service to personalise Map Colouring 9 Domain Architecture ServerClient BrowserWebserver Web Map Client Server (SLD-) WMS Geodata Server User Data Personali- sation Webserver (Service) Colouring Proxy

10. Joerg Steinruecken 17.11.09 A Web Service to personalise Map Colouring 10 Domain Architecture - Personalisation ServerClient BrowserWebserver Web Map Client Server (SLD-) WMS Geodata Server User Data Personali- sation Webserver (Service) Colouring Proxy

11. Joerg Steinruecken 17.11.09 A Web Service to personalise Map Colouring 11 Personalisation Creation of user profiles (user name, password,…) Getting personal data –Colour vision impairment specified by users Users have to evaluate test images –Display‘s colour reproduction and ambient light Display calibrated? Visual calibration by gamma adjustment Users have to evaluate test images

12. Joerg Steinruecken 17.11.09 A Web Service to personalise Map Colouring 12 Domain Architecture – Map request ServerClient BrowserWebserver Web Map Client Server (SLD-) WMS Geodata Server User Data Personali- sation Webserver (Service) Colouring Proxy

13. Joerg Steinruecken 17.11.09 A Web Service to personalise Map Colouring 13 Domain Architecture – Map request ServerClient BrowserWebserver Web Map Client Server (SLD-) WMS Geodata Server User Data Personali- sation Webserver (Service) Colouring Proxy

14. Joerg Steinruecken 17.11.09 A Web Service to personalise Map Colouring 14 Domain Architecture – Map request ServerClient BrowserWebserver Web Map Client Server (SLD-) WMS Geodata Server User Data Personali- sation Webserver (Service) Colouring Proxy WMS-URL

15. Joerg Steinruecken 17.11.09 A Web Service to personalise Map Colouring 15 Domain Architecture – Map request ServerClient BrowserWebserver Web Map Client Server (SLD-) WMS Geodata Server User Data Personali- sation Webserver (Service) Colouring Proxy GetCapabilties

16. Joerg Steinruecken 17.11.09 A Web Service to personalise Map Colouring 16 Domain Architecture – Map request ServerClient BrowserWebserver Web Map Client Server (SLD-) WMS Geodata Server User Data Personali- sation Webserver (Service) Colouring Proxy SE

17. Joerg Steinruecken 17.11.09 A Web Service to personalise Map Colouring 17 Domain Architecture – Map request ServerClient BrowserWebserver Web Map Client Server (SLD-) WMS Geodata Server User Data Personali- sation Webserver (Service) Colouring Proxy SE-URL SE

18. Joerg Steinruecken 17.11.09 A Web Service to personalise Map Colouring 18 Domain Architecture – Map request ServerClient BrowserWebserver Web Map Client Server (SLD-) WMS Geodata Server User Data Personali- sation Webserver (Service) Colouring Proxy GetMap SE

19. Joerg Steinruecken 17.11.09 A Web Service to personalise Map Colouring 19 Domain Architecture – Map request ServerClient BrowserWebserver Web Map Client Server (SLD-) WMS Geodata Server User Data Personali- sation Webserver (Service) Colouring Proxy GetMap SLD=SE-URL SE

20. Joerg Steinruecken 17.11.09 A Web Service to personalise Map Colouring 20 Domain Architecture – Map request ServerClient BrowserWebserver Web Map Client Server (SLD-) WMS Geodata Server User Data Personali- sation Webserver (Service) Colouring Proxy

21. Joerg Steinruecken 17.11.09 A Web Service to personalise Map Colouring 21 Approach of colouring Visual Distinguishability Colour space, providing an appropriate metric (visual equidistance) Formulation of an optimisation problem: Maximise the minimal distance between colours Solution on demand Modelling the colour space: 3D-Polyhedron

22. Joerg Steinruecken 17.11.09 A Web Service to personalise Map Colouring 22 Process of colouring sRGB Standard-RGB

23. Joerg Steinruecken 17.11.09 A Web Service to personalise Map Colouring 23 Process of colouring sRGB XYZ CIE-XYZ colour space

24. Joerg Steinruecken 17.11.09 A Web Service to personalise Map Colouring 24 Process of colouring sRGB XYZCIELUV CIE L* u* v* colour space

25. Joerg Steinruecken 17.11.09 A Web Service to personalise Map Colouring 25 Process of colouring sRGB XYZCIELUVMAXMIN

26. Joerg Steinruecken 17.11.09 A Web Service to personalise Map Colouring 26 Process of colouring sRGB XYZCIELUVMAXMIN

27. Joerg Steinruecken 17.11.09 A Web Service to personalise Map Colouring 27 Optimisation problem Set of m given colours Set of n colours which have to be determined Parameters of hyperplanes which form the polyhedron maximise subject to Euclidean Distance objective constraints

28. Joerg Steinruecken 17.11.09 A Web Service to personalise Map Colouring 28 Problem characteristics Nonlinear problem –Large number of local optimal solutions –Efficient algorithms find a locally optimal solution, but usually not the globally optimal solution Global Optimum Local Optima Rastrigins function (source: Matlab)

29. Joerg Steinruecken 17.11.09 A Web Service to personalise Map Colouring 29 Behaviour of efficient algorithms Local Optimum Global Optimum Fundamental importance of starting points‘ location

30. Joerg Steinruecken 17.11.09 A Web Service to personalise Map Colouring 30 Algorithm Finding appropriate starting points Method of local optimisation Detect suboptimal solutions Nearly global optimal solution S1 S2 S3

31. Joerg Steinruecken 17.11.09 A Web Service to personalise Map Colouring 31 Observation: To use the colour space in the best possible way, the majority of points have to lie on the polyhedron‘s boundary. Conclusion: Points which are placed on the boundary are well suited as starting points S1: Appropriate starting points

32. Joerg Steinruecken 17.11.09 A Web Service to personalise Map Colouring 32 S3: Detect suboptimal solutions Given points Voronoi vertices intersection of Voronoi edges and polygon Vertices of the polygon Find an improvement Candidats are given by the Voronoi-Diagram Example in 2D:

33. Joerg Steinruecken 17.11.09 A Web Service to personalise Map Colouring 33 Personal information Incorporation of users‘ personal information as constraints –Color vision impairment: Finding colours in a plane –Colour reproduction & ambient light: Clipping the colour space

34. Joerg Steinruecken 17.11.09 A Web Service to personalise Map Colouring 34 Personalisierung Befragung Tour 1 Tour 2 Tour 4 Tour 5 Tour 6 Tour 7 Tour 3 Legend

35. Joerg Steinruecken 17.11.09 A Web Service to personalise Map Colouring 35 Conclusions Concise maps by selection of well distinguishable colours Formulation of an optimisation problem –distinguishability = Euclidean distance Efficient identification of a nearly optimal solution Algorithm: Find appropriate starting points, local optimisation method, geometric evaluation Adaptation to users‘ individual requirements Usable as Web Service Prototype will shortly be available on http://colour.ikg.uni-bonn.de

36. Joerg Steinruecken 17.11.09 A Web Service to personalise Map Colouring Thank you for your attention