1. halo patrick baudisch, microsoft research, LDUX* & ruth rosenholtz, parc, ASD april 10 th, CHI 2003 *while at xerox parc, now parc inc.

2. + the problem

3. halo

4. contents halo is not a focus plus context technique (related work) halo is a lamp shining onto the street (designing halo) halo is 16-33% faster than arrow-based visualization techniques (user study) build interactive halo applications! (conclusions, lessons learned)

5. related work driving directions vs. route planning aids overview-plus-detail focus-plus-context pointing into off-screen space

6. halo design

7. cinematography 1.entry and exit points 2.point of view arrow-based techniques 3.partially out of the frame halo rings are familiar, graceful degradation

8. streetlamps aura visible from distance aura is round overlapping auras aggregate fading of aura indicates distance what we changed smooth transition sharp edge disks rings dark background light background

9. intrusion border handle space for arcs… and for corner arcs reserve space for content

10. arc length = distance

11. handling many objects find best (restaurant): relevance cut-off see all (dangers): merge arcs

12. app designers can use color texture arc thickness

13. user study

14. interfaces arc/arrow fading off scale 110-300m/cm map as backdrop readability ok same selectable size hypothesis: halo faster halo ring distance from display border legend

15. pre-study to define tasks 8 participants (6 GPS users, 2 PDA users) informal interviews 10-40 minutes 4 tasks to be used in study

16. 1. locate task click at expected location of off-screen targets had to simulate on PC

17. 2. closest task click arrow/arc or off-screen location closest to car

18. 3. traverse task click all five targets so as to form shortest path

19. 4. avoid task click on hospital farthest away from traffic jams

20. procedure 12 participants within subject design, counterbalanced four training maps per interface/task, then eight timed maps questionnaire

21. task completion time TaskArrow interfaceHalo interface Locate20.1 (7.3)16.8 (6.7) Closest9.9 (10.1)6.6 (5.3) Traverse20.6 (14.1)16.8 (8.7) Avoid9.2 (4.7)7.7 (5.8) 33% 16%

22. error rate TaskArrow interfaceHalo interface Locate23.5 pixels (21.6)28.4 pixels (33.8) Closest22% (42%)21% (41%) Traverse97.4 pixels (94.7)81.0 pixels (96.7) Avoid15% (35%)14% (34%) participants underestimated distances by 26% participants saw ovals (gestalt laws?) we can compensate for that: width += 35%

23. subjective preference

24. conclusions halo 16%-33% faster than arrows –no split attention –distortion-free space –scale independent –no need to annotate distance –perceive all rings at once [treisman & gormican] limitation: max number or rings future work: applications where peripheral objects move and change

25. Thanks! try halo: http://www.patrickbaudisch.com/projects/halo polle zellweger, jock mackinlay, lance good, and mark stefik ( citylights short paper talk) scott minneman and allison woodruff

26. end

27. Extra

28. (a) locate(b) closest (d) avoid(c) traverse