Limn: Using Movie Technology
to Drive Graphics for Large Data
Manuel Suarez†, Dianne
Cook†, Peter Sutherland‡,
Justin McIllece†.
†
Iowa State University
‡
Affymetrix, Inc.
Project Description
Explore for multivariate structure in
massive data.
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.
2
JSM 2001 - Atlanta
August 8, 2001
Topics of Discussion





3
Visualizing Multivariate Data
Extensions to Large Data
Application
Software Demo
Limitations/Continuing Work
JSM 2001 - Atlanta
August 8, 2001
What is Multivariate Data?
Matrix of data: cases=rows, variables=columns
 x11
x
21

X
 

 xn1
4
x12

x22



xn 2

JSM 2001 - Atlanta
x1 p 

x2 p 
 

xnp 
nxp
August 8, 2001
Visualizing Multivariate Data
Multiple Views Paradigm,
Augmented by:
•Focusing using zoom/pan/re-scale
•Linking by queries, or motion
•Rearranging to make multiple comparisons
5
JSM 2001 - Atlanta
August 8, 2001
Touring Algorithm
Interpolate between a series of projection
planes  joint distribution/multivariate shape
X ( nxp ) P( px 2 )  Y( nx 2 )
6
JSM 2001 - Atlanta
August 8, 2001
Touring Algorithm (cont.)




7
Grand: random choice of base
planes
Guided: functional choice of base
planes
Manual: User controlled
interpolation
Neil Sloane’s “Equi-distant” Bases
JSM 2001 - Atlanta
August 8, 2001
Visualization of Large Data Sets

Data Reduction
–
–

Scaling of Methods
–
–
8
Binning – Lose intricate structure
Subset – Lose rare structure
Computation
Storage
JSM 2001 - Atlanta
August 8, 2001
Limn Software
Two Steps:
1.
2.
Create and animation sequence,
and save as QuickTime movie or
series of JPEG images
View animation, and interact with
it by brushing, and overlaying
subsets of data.
* Code is written in Java
9
JSM 2001 - Atlanta
August 8, 2001
Data of Interest
Multivariate Spatio-Temporal Data, e.g.
continuously-recording monitoring stations or
remotely sensed data.
Movie
Space
S M T W Th F S
Time
10
JSM 2001 - Atlanta
August 8, 2001
Test Data Set

11
Monitoring global climate using Pacific Ocean
moorings measuring temperature, wind, …
JSM 2001 - Atlanta
August 8, 2001
Demo


Background Movie: All data, 1980-1998
Subset Overlays
–
–
–
–
–
12
December 1993, Eastern Pacific (Normal year)
December 1993, Western Pacific
December 1997, Eastern Pacific (El Niño year)
December 1997, Western Pacific
Binned Data
JSM 2001 - Atlanta
August 8, 2001
Limitations/Continuing Work

User Interface
–
–
Create subsets by space and time
Composite movie layers for subsets



Database
–
–
–
13
For large subsets
For viewing density
Distributed data and live updating of data
Fast Indexing for linked views (e.g., space-time)
Catalog movies of full data and subsets
JSM 2001 - Atlanta
August 8, 2001
Summary



14
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
JSM 2001 - Atlanta
August 8, 2001
Contact Information
www.public.iastate.edu/~dicook/Limn/index.html
Email: dicook@iastate.edu
suarezm@vrac.iastate.edu
15
JSM 2001 - Atlanta
August 8, 2001