Limn: Using Movie Technology to Drive Graphics for Large Data Manuel Suarez †, Dianne Cook †, Peter Sutherland ‡, Justin McIllece †. † Iowa State University ‡ Affymetrix, Inc.

August 8, 2001 JSM Atlanta 2 Project Description Limn (lîm), v.t.; to present an image or lifelike imitation of; Limit-n; to be able to explore any data set to its limits. Explore for multivariate structure in massive data.

August 8, 2001 JSM Atlanta 3 Topics of Discussion Visualizing Multivariate Data Extensions to Large Data Application Software Demo Limitations/Continuing Work

August 8, 2001 JSM Atlanta 4 What is Multivariate Data? Matrix of data: cases=rows, variables=columns

August 8, 2001 JSM Atlanta 5 Visualizing Multivariate Data Multiple Views Paradigm, Augmented by: Focusing using zoom/pan/re-scale Linking by queries, or motion Rearranging to make multiple comparisons

August 8, 2001 JSM Atlanta 6 Touring Algorithm Interpolate between a series of projection planes  joint distribution/multivariate shape

August 8, 2001 JSM Atlanta 7 Touring Algorithm (cont.) Grand: random choice of base planes Guided: functional choice of base planes Manual: User controlled interpolation Neil Sloane’s “Equi-distant” Bases

August 8, 2001 JSM Atlanta 8 Visualization of Large Data Sets Data Reduction – Binning – Lose intricate structure – Subset – Lose rare structure Scaling of Methods – Computation – Storage

August 8, 2001 JSM Atlanta 9 Limn Software Two Steps: 1. Create and animation sequence, and save as QuickTime movie or series of JPEG images 2. View animation, and interact with it by brushing, and overlaying subsets of data. * Code is written in Java

August 8, 2001 JSM Atlanta 10 Data of Interest Multivariate Spatio-Temporal Data, e.g. continuously-recording monitoring stations or remotely sensed data. S M T W Th F S Space Time Movie

August 8, 2001 JSM Atlanta 11 Test Data Set Monitoring global climate using Pacific Ocean moorings measuring temperature, wind, …

August 8, 2001 JSM Atlanta 12 Demo Background Movie: All data, Subset Overlays – December 1993, Eastern Pacific (Normal year) – December 1993, Western Pacific – December 1997, Eastern Pacific (El Niño year) – December 1997, Western Pacific – Binned Data

August 8, 2001 JSM Atlanta 13 Limitations/Continuing Work User Interface – Create subsets by space and time – Composite movie layers for subsets For large subsets For viewing density Database – Distributed data and live updating of data – Fast Indexing for linked views (e.g., space-time) – Catalog movies of full data and subsets

August 8, 2001 JSM Atlanta 14 Summary A new approach to visualizing large, multivariate data Combine pre-computed tour movies of large data with real-time computed subsets Extends tour algorithm to arbitrarily large data sets

August 8, 2001 JSM Atlanta 15 Contact Information