Multidimensional Visualization

David Yucht

ICS 280

Spring 2001

The Problem at Hand

How do we work with the constraints of our reality (3 Spatial Dimensions + Time/Motion) in order to visualize data sets containing potentially infinite numbers of attributes (n-Space)?

Potential Solutions

Question is moot for < 3 attributes For > 3 attributes

– Use complex 2D displays– Use multiple 3D displays– Add other distinguishing image properties– Use another medium such as sound

Why use 3D?

Utilizes all Euclidian spatial dimensions Humans have an innate ability to process 3D

images quickly without much effort Images can be enriched with other properties

– Time/Motion (4D)– Color– Texture– Shape

Problems with 3D

Computationally expensive True 3D Output & Interaction requires special

equipment Navigation can be difficult Data with > 3 attributes require multiple 3D

images and/or additional properties Depth & Occlusion

Early Test Systems

W. Wright: Information Animation Applications in the Capital Markets

Feiner & Beshers: Worlds Within Worlds: Metaphors for Exploring n-Dimensional Virtual Worlds

Information Animation

4D System for visualizing financial markets Displays Equity & Bond markets in real-time Scalable from 1 stock to entire markets Allows for querying of in-depth information

upon request Utilizes movement/animation to alert users to

events and give a “feel” for the market

Information Animation (2)

Animation takes advantage of human visual processing– 4 systems within visual cortex

1 handles motion 1 handles color 2 handle object form

The system thus uses motion, colors, shapes, and sizes to represent information

Financial Properties - Equity

Price Net changes (days, weeks, quarters, etc.) Trading Volume Volume at a Price Trades at bid Trades at offer

Financial Properties – Bond

Price Net changes Trading Volume Interest Rates Yield curve (instantaneous & historical)

Significance of Info Animation

3D can hold 10x or more data than 2D 3D allows users to more quickly see market trends 4D allows users to examine spreads as they occur Eases interaction & dimensional transformation

problems by allowing queries Avoids occlusion problem by relying on display design

and image arrangement

n-Vision

Testbed system for representing n-Dimensions Uses true 3D imaging for display & interaction

– Stereoscopic shutter glasses– VR DataGlove

Handles n-Space to Euclidian spatial transformation by nesting 3D images within one another

n-Vision (2)

Does utilize motion; can be considered a 4D system

Does not utilize other image properties such as texture and color to represent attributes

Nesting Worlds

n-Vision nests multiple 3D images in order to perform dimensionality reduction; it slices away dimensions

Each 3D image is displayed on top of another, with reference marks to illustrate the values where that particular slice lies

Uses recursive parent-child relationships to display & control multiple images

The Significance of n-Vision

Provides a metaphor for > 4D visualizations Sidesteps the occlusion problem with true 3D

interaction– Users can grab and rearrange images– Stereoscopic images give accurate representation

of depth– Provides other tools such as the dipstick and

waterline to further reduce occlusion and user confusion