1. EURESCO : GeoVisualization Defining Geovisualization Contents for Users Needs A Computer Science ViewpointSoftware Development Jason DykesDept. of Information ScienceCity University, London

2. 1. Introduction : Jason Dykes (!) • Background : • Geography (BA) / GI (Masters) • Programming ‘self-taught’ • PhD Interactive Cartography • Dept. of Information Science • School of Informatics • Roles : • Technique developer / Tool designer • User group requirements • Suggesting techniques • Implementation in software • Requires • Research • Communication

3. 1. Introduction : Outline • Reflections on software development for visualization • Interaction / Flexibility • Roles and Processes • Individuals • Community • Focus : ‘Software Development’ • Examples • Scripting • Graphics • Software / Designs • Points for Discussion?

4. 2. Visualization : Supporting Ideation • Flexibility / Interactivity is the key ... • information : known / unknown • audience : public / private • How do we instruct computers ?

5. eda / visualization systems programming scripted toolkit visual programming knowledge acquisition flexibility Binary / ByteCode Operating System Software Development Software Use efficiency 2. Visualization : Supporting Ideation

6. 2. Visualization : Methods of ‘Interaction’ APPLICATION USER limited by application. decisions on design / interaction / flexibility made below. flexibility in software / support? generates ideas, employs / instructs below, tests and uses applications for visualization semi-flexible software, generate intellectual design from data and set of functions (scripts, code, data flow?) links functionality from below, generates intellectual design, less flexibility / more speed? links functionality from below, generates intellectual design, high flexibility / high speed formal structured instructions, develops software components for above INVESTIGATOR DESIGNER VISUAL PROGRAMMER SCRIPTER SYSTEMS PROGRAMMER

7. 3. Advancing Visualization

8. 3. Advancing Visualization : ‘Intellectual Design’ • "Design is a complex process" • Conventional map : abstraction, transformation, selection, genztion, symbztion, visual composition, figure-ground, hierarchies, arrangement. • Compromises & constraints : scale, use, presentation format, area coverage, precision • Dynamic maps : more design constraints, more varied media, tools for interaction. • No. of solutions computationally explosive • Gahegan provides some figures (without interactive controls!) • ‘Intellectual Design’ • Some advice available - needs testing • Metadata important (Information Science - possibilities) • PROGRAMMING ... the bottom line in flexibility

9. flexibility efficiency 4. Flexibility / Efficiency / Interaction • Need to make software more flexible • Need to make development more efficient Approaches : • Agreed standards • Collaboration • Reusable components • Extensibility • Alternative APIs Technologies : • Java • Java Beans • VRML / Java EAI • VB / ActiveX • Tcl / Tk Examples : • Open GIS • VFC • NetGIS • GeoTools (?) • GeoVRML • GeoVISTA Studio • GPL / nViZn • SVG (XML) • InonaGIS (?)

10. 4. Flexibility : Scripting • High level languages connect existing software tools & functions • Created in complimentary systems programming languages • Trade-off : ease of use/flexibility vs speed • Faster machines and better languages make it appealing : • Python, VB, UNIX shells, JavaScript, Tcl/Tk • Systems Prog - complexity in data structures and algorithms • Scripting - complexity in the connections : • e.g. GUI • Existing functionality defines widgets • Scripts – behaviour, appearance, connections, function • e.g. Dynamic map - ‘intellectual design’ • Existing functionality defines symbolism & interaction possibilities • Scripts – behaviour, appearance, connections, function

11. 4. Flexibility : Scripting in Tcl/Tk • Tcl : Tool Command Language • variables, control flow, procedures, ability to run external programs, operating system services. • Tk : Graphic Toolkit • 1990 - GUI widget types • 1992 - ‘canvas’ - coordinate space and graphic symbols Advantages : • Rapid prototyping – MSc GIS • Platform independence • Extensibility & extensions • Debugging messages • Source development • User community • ACM Recognition Disadvantages : • Status / support? • Lack of rigour! • Not geographic • ‘Complex’ API • Limited multimedia object types* • Links to systems prog. language* • Limited 3D*

12. 5. Example Designs • Implementation / Benchmark / Intellectual Design cdv panoraMap VFC geo-centric ||-plots speed space/time

13. 5. Examples : Space/Time EDA • Get these from DataViz II

14. 5. Examples : Space/Time Spotlights

15. 5. Examples : Space/Time Spotlights

16. 5. Examples : Space/Time Spotlights

17. 5. Examples : Space/Time SFNs

18. 3. Advancing Visualization (again)

19. 6. Learning / Collaboration • Organisations (public / private) • Project management • Computing • graphics • ‘programming’ (intelligent) • hci / usability • software development / engineering / architecture • databases • Other specialist subject areas • psychology • etc. (e.g. Issac Brewer) • Is ‘GIS Inertia’ an obstacle?

20. 7. Themes : Conference Summary • What can be done with visualization? • Examples • Broad Perspective • How can the user interact with visualization environments? • Explicitly expressed and addressed How can people best do geovisualization? Intelligence Augmentation? • Linking disparate data sets • panoraMap • VFC hub • Interdisciplinary approach • Implicit

21. 7. Themes : for Discussion? • Interdisciplinary approach • collaboration required • Visualization / ‘Software Development’ … broad definition • SSR - ‘Could you do this for me … ?’ • DMM - ‘Is this possible in Java?’ • Multi-level development / API required • Communication / standards vital • e.g. Open GIS Consortium? • Means of evaluation : Web Cartography Forum? Test datasets? • Expertise exists in Computer Science : • We’re all computing! • We need to keep looking & learning!