Tree-Maps Cyntrica Eaton February 11, 2001 A Space-Filling Approach to the Visualization of Hierarchical Information Structures Brian Johnson Ben Shneiderman

Sneak Peek

A B C D EF BCD

Overview Part I: Tree-Maps Introduction Traditional Data Display Tree Maps Contributions

Overview Part II: Paper Characteristics Critique Favorite Sentence References Current State

Part I

Introduction Hierarchical Data Organization Charts Family Trees Animal Phyla Library Catalogs Visualizations display relationships among data Effective data presentation has posed a problem

Introduction Hierarchical Data Presentation: Text-Based Connection Enclosure I. II. A. B. C. D. E. F. a. b. c. a. b. c A. B. C.

Introduction Hierarchical Data Presentation: Text-Based Connection Enclosure A B C D EF

Introduction BCD Hierarchical Data Presentation: Text-Based Connection Enclosure

Connection A B C D EF Contain structural information and node content Generally easy to lay out and interpret Excellent visualization tools for small data sets Exploit human ability to quickly recognize l relationships among entities based on l spatial configuration.

Connection A B C D EF As data set gets larger, the information space l l gets harder to see - Amount of information shown can be far l less than user is capable of processing - User becomes more responsible for l l l l l recalling information and tree node location Node-link diagrams contain great deal of e empty space

Motivation Objective: To produce a compact visualization of a directory l tree structure Expected Benefits: View large file directories in a constrained space Locate large files quickly and easily Determine which users consume more disk space

File Directory

Tree Diagram Desktop My DocumentsMy Computer …. Recycle BinACL60 …. ………… DFS Lexicon Grammar …. BFSAllegro

Venn Diagram Desktop My Docs My Ntwk Recycle Bin My Comp ACL60

Tree-Map My DocMy Comp My Ntwk Recycle ACL60

Tree-Maps Use entire information space Effective for showing quantitative properties of data Interactivity allows users to become more connected with l l data display

Tree Diagram Desktop My DocumentsMy Computer …. Recycle BinACL60 …. ………… DFS Lexicon Grammar …. BFSAllegro

Tree-Map My DocMy Comp My Ntwk Recycle ACL60

A B C D EF Tree-Map Construction NodeWeight A10 B1 C4 D5 E2 F3

B: 1 A: 10 C: 4 D: 5 E: 2F: 3 Tree-Map Construction A B C D EF

A B C D EF A

A B C D EF BCD

A B C D EF BCD

Contribution Introduces a method of enclosure to allow human visualization of large amounts of hierarchical data in a constrained information space.

Part II

Critique Strengths: Concise Well developed Weakness: Had to read it a couple of times to get a full understanding of how tree-maps are constructed

Favorite Sentence The Tree-Map visualization technique makes 100% use of the available display space, mapping the full hierarchy onto a rectangular region in a space-filling manner.

References Data Visualization Human ability to grasp l graphical information Color Coding Similar studies Tree Maps: A Space-Filling Approach to the Visualization of Hierarchical Information Structures _______________ _______________ _______________ _______________ _______________ _______________

References Data Visualization Offspring work Visual mapping techniques Hierarchical information l display Tree Maps: A Space-Filling Approach to the Visualization of Hierarchical Information Structures _______________ _______________ _______________ _______________ _______________ _______________

Current State Applications: Disk Mapper NBA Statistics Stock Portfolio Visualization PhotoMesa

NBA Statistics NBA Atlantic CentralMidwest Pacific ……………………. ………………… …………… LakersSuns Kings ……………

NBA Statistics

Stock Portfolio

PhotoMesa

Current State Research: Incorporating even larger data sets and allowing them to be readable Supporting data animation Creating better data views

Current State

Conclusion Efficient Space Utilization: Great for large information structures Interactivity: User control in the presentation of data Comprehension: Rapid extraction of information with low perceptual l and cognitive loads Aesthetics: Visually pleasing rendering of data