The document discusses the concept and applications of treemaps in managing metadata and visualizing data, particularly in the context of Web 2.0 tagging systems. It explores various algorithms for creating treemaps, shares success stories of their implementation across different platforms, and concludes that while treemaps provide compelling information representation, challenges remain in displaying hierarchical structures effectively. The document highlights the potential for non-rectangular solutions and emphasizes the value of zoomable interfaces in data visualization.

1. Browsing Information with TreeMaps Sebastian Ryszard Kruk Sebastian Ryszard Kruk [email_address] Reading Group 6/09/2006 DERI, Galway

2. Outline Motivation – managing “flat” metadata Introduction to TreeMaps Idea Algorithms Success stories – history of the TreeMaps TreeMaps and tagging DEMO: My deli.icio.us and TreeMaps Conclusions

3. Motivations Free tagging in Web 2.0 is a nice thing ... ... but how to find information with so many tags? ... and the problem gets worse when we stumble upon multiple facets

4. TreeMaps - The Idea Original motivation – managing large, shared disk space the term 'treemap' describes the notion of turning a tree into a planar space-filling map http://www.oreillynet.com/ruby/blog/2006/07/treemap_on_rails.html

5. TreeMaps - Algorithms Binary Tree Ordered Treemap Pivot by middle Pivot by size Pivot by split size Slice Squarified Strip treemap

6. TreeMaps strip algorithm

7. TreeMap - MBA David Turo built a treemap system with a fixed-level hierarchy used in sports application: 453 basketball players, organized into the 27 teams in four leagues of the NBA. http://www.cs.umd.edu/hcil/treemap-history/treemap-nba.gif

8. Success stories - SmartMoney Shows 535 popularly held stocks, organized by industry groups, size-coded by market capitalization, and color-coded to show rise or fall http://www.smartmoney.com/marketmap/mapPage.cfm

9. Success Stories – MS Netscan Treemaps applied to the Netscan project, to data mine and visualize Usenet, one of the largest collections of social cyberspaces (Marc Smith, Microsoft Research) http://netscan.research.microsoft.com

10. Success Stories – Google News Newsmap showing the Google News output (Marcos Weskamp, April 2004) http://www.marumushi.com/apps/newsmap/newsmap.cfm

11. Success Stories - PhotoMesa PhotoMesa is a zoomable image browse using Piccolo.NET Toolkit http://www.photomesa.com/

12. Pebbles - Circular TreeMaps Pros: Zooming in on directories could be very fast because the layout doesn't need to be recalculated. The aspect ratio of nodes is always the same. Cons: They don't fill the available space completely. They fill the available space to a varying degree which in the case of nested tree structures leads to the problem that circles of the same size could represent files (or folders) of a vastly different size

13. Voronoi TreeMaps A treemap data visualization that uses Voronoi tesselations (a polygon-based subdivision algorithm) It attempts to avoid the problems with: the aspect ratio of the rectangles identifying the visualized hierarchical structure. Allows for creating treemap visualizations within areas of arbitrary shape, such as triangles & circles http://infosthetics.com/archives/2006/01/voronoi_treemap_data_visualization.html

14. TreeMaps and Tagging Greasemonkey user script which alters the content of the web page when browsing connotea by inserting a treemap of the current tags using SVG http://www.urbigene.com/gmconnoteasvg/

15. TagsTreeMaps for del.icio.us AJAX+JSP component Using del.icio.us as a test source of tags Pre-processing (Clustering, Tree-pruning) Flitering Tag name matching (with name expansion through WordNet) Size/coverage matching Selection [ work in progress ] Post-processing (Coloring) User can select treemaps algorithm Zoomable interface

16. Tags TreeMaps - DEMO http://localhost:8080/lab/

17. Conclusions Tag clouds does not have to be the best information representation for Web 2.0 Even basic implementations of treemaps deliver interesting solutions One of the main drawbacks is representing the tree structure inside , what leads to unreadable labels There is a huge potential in non-rectangular solutions and adaptation of the zoomable interface paradigm http://del.icio.us/skruk/treemaps