INFORMATION MURAL A technique for displaying and navigating large information spaces Dean F. Jerding and John T. Stasko Graphics, Visualization, and Usability Center College of Computing Georgia Institute of Technology

MOTIVATION Global visualizations for large data sets are constrained by the limited number of pixels on the screen scalability problem addressed

WHAT IS INFORMATION MURAL ? Information mural is a –2D, miniature representation –representing an entire information space –using visual attributes such as color and intensity to portray information density

OBJECTIVES Create a representation of a large information space on the screen Mimic the original visual representation Minimize the loss of information in the compressed view

AUTOMOBILE DATA Standard parallel coordinate view of the data

AUTOMOBILE DATA Mural of a parallel coordinate view of automobile data showing MPG, engine displacement, horsepower, weight, acceleration, and model year (1970 – 1982)

AUTOMOBILE DATA Color overlaid for number of cylinders (3 = red, 4 = orange, 5 = yellow, 6 = green, 8 = cyan).

THE TECHNIQUE First present the global view to the user –Scale the original visualization –Make explicit the density of overlap of information visually apparent (using colors) Allow user to analyze or navigate the global view for detailed views on the items of interest

INFORMATION DENSITY REPRESENTATION This is the distinguishing feature of this paper. Problem –Many pixels on the original image contribute to a single pixel in the mural –Each pixel in the mural can have a single color Constraints –Cannot resort to using the RGB components

INFORMATION DENSITY REPRESENTATION Some earlier approaches are –Aggregation –Sampling Solution Color the pixel according to the attribute color that occurs most frequently in that pixel

THE BIGGER PICTURE MURAL ORIGINAL IMAGE

INTENSITY MAPPING(cont) 1. Construct a unit square connecting the centers of the surrounding four destination pixels

INTENSITY MAPPING (cont) 2. Using the scaled location of the center of the original pixel to divide the square into four quadrants

INTENSITY MAPPING (cont) 3. The area of the quadrant diagonally opposite to each of the four destination pixels is the amount of intensity contributed by that pixel

SUITABLE FOR ? Navigating information spaces Studying the characteristics of geographic/spatial data Discovering attributes and relationships

A CLOSER LOOK…… Parallel program message trace diagram drawn by just overplotting Mural of parallel program message trace

SUN SPOT MURAL Mural of the number of sun spots recorded daily,

SUN SPOT MURAL Mural of the number of sun spots recorded daily, , zoomed in on a small area

SUN SPOT MURAL View of sun spots showing focus area and mural of entire data set at the bottom.

DOCUMENT VISUALIZATION

Murals showing keyword distribution for search on ``visualization'' (yellow), ``object-oriented'' (green), and ``OO'' (cyan) in three documents

OPINIONS A new approach to representing of data density Examines all the points in the source image – may be slower For very large data mural becomes fuzzy Colors - double edged sword –helps in identifying strong patterns –noticing the colors –appropriateness of colors

HCI METRICS User satisfaction - good Learning time - good User Performance } depends Error rate } on Retention } visualization

Thank you