1. Hyperbolic Trees A Focus + Context Technique http://www.acm.org/sigchi/chi95/proceedings/papers/jl_bdy.htm John lamping Ramana Rao Peter Pirolli Joy Mukherjee

2. Essentials Visualizing Hierarchies Features -More space to a part -Still maintain context Scheme -Lay out on hyperbolic plane -Map this to a circular display

3. Inspiration Escher woodcut -Size diminishes outward -‘devilish’ growth in no. of components -Uniformly embedding an exponentially growing structure Space available to a node with all its children falls of continuously with distance from the center

4. Related Work Peer work -Document Lens -Perspective Wall -The Cone Tree -Tree Maps -Prune and Filter Problems -None provide a smooth blend of focus + context

5. Issues Layout Mapping and Representation Change of focus Node Information Preserving Orientation Animated Transitions

6. Layout Features -Circumference and area of circles grow exponentially with radius -Recursive algorithm laying out each node based on local information -Divergence of parallel lines on a hyperbolic plane -Easy implementation -Required only once

7. Layout Mechanism -Allocate a wedge of the hyperbolic plane to each node -Place children along an arc in the wedge -maintain distance from itself and between the children -Recurse on each child -Each wedge retains the same angle

8. Layout Variations -non-uniform trees * allocate larger wedge to sibling with more children *decreases variation in node separation -using less than 360° *put all children in one direction

9. Mapping and Representation Poincar\’e model ( conformal mapping ) -preserves angles -distorts lines into arcs Klein model -preserves lines, distorts angles Cannot have it both ways Poincar\’e preferred -points near the edge get more screen area than in Klein's model.

10. Change of Focus Rigid transformation of hyperbolic plane Mapping the new plane back to the display Multiple transformations -compose into single transformation -avoids loss of floating point precision Compute transformation for nodes with display size at least one pixel -Bound on redisplay computation

11. Node Information Features -circles on the hyperbolic plane are circles on the Euclidean disk -decrease in size with distance from center Mechanism -display node information based on the circular area available for the node

12. Preserving Orientation Rotation - translation on the hyperbolic plane causes the display to rotate -may lead to different view of a node when revisited -nodes further from the line of translation rotate more Solution -most direct translation between points specified + a rotation about the point moved

13. Preserving Orientation Approaches for adding rotation -always keep original orientation of the root *hence all nodes maintain their original orientations -explicit lack of orientation *node in focus fans out in one and only direction *hence each node is viewed in one and one way only

14. Animated Transitions Maintains object constancy Helps user assimilate changes across views Generated using ‘n th -root’ concept Bottleneck – display performance Compromises for quick redisplay -draw less of the fringes -draw lines rather than arcs -drop text during animation

15. Pros and Cons Pros -Easy blending between focus and context -Avoids distortion and hiding of information -Scaling up to 10 times + space for text Cons -May lead to cramping if each node has several children -Not much accompanying information

16. Evaluation Learnability -* * * * * Retention -* * * * * Ease of use -* * * * * Error recovery -* * * * User satisfaction -* * * *

17. It’s over ! Yoohooo !!!! No questions … Pleeeeeeeeaaaaasseeee !!!!