Bertin.ppt

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Graphics and

Graphic Information Processing

J. Bertin

Presented by Fusun Yaman

Overview

Introduction

Description of the paper

My favorite sentence

Contributions

Notes on the references

Critique

What happened to this topic

Introduction

Section from Graphics and Graphic

Information Processing

(1977/1981)

Problem addressed in section B

Collection of objects that are described by n characteristics

How to graphically represent this information when usually n > 3

Terminology

Information is in Data Table

Objects correspond to cases (A, B, C, D)

Characteristics correspond to variables

(income,education, experience)

A B C D

Income

Education

Experience

Terminology (continued)

Objects can be

Ordered (0) , like months

Reorderable (

), like individuals

Topographic (T), like cities

Characteristics can be

Nominal, like movie titles

Ordinal, like movie ratings

Quantitative, like length of the movie

“Impassable barrier”

Image has only 3 dimensions

This barrier is impassable

Le n be number of variables (rows)

 n

3 : Use scatter plots

 n > 3 : Other solutions needed

Solutions for n > 3

Constructing several scatter plots

Sacrificing overall relationship

Constructing a matrix

Overall relationship is discovered by permutations

Synoptic

Classifies graphic constructions according to two properties of Data Table

If n is number of characteristics

 n > 3 and n

3

Nature of objects

 Ordered , reorderable, topographic

Graphics for n

3

Matrix construction when objects are reorderable

Graphics for n

3

Arrays of curves when objects are ordered

Graphics for n

3

Scatter plots for both reorderable and ordered cases

Third row is represented by the size of the marker (9)

Graphics for n

3

In topographies bi- or tri-chromatic superimposition reveals the overall relation ships

Graphics for n > 3

Objects and characteristics are reorderable ( 

)

Reorderable matrix

Objects are ordered, characteristics are reorderable

Image file (2)

Array of curves when slops are meaningful (3)

Ordered objects and characteristics

Collection of tables or maps (4,5)

Use super imposition to discover similar groups

Reorderable Matrix

Objects and characteristics are reorderable (



)

Permutable in x and y

Overall relationship is discovered by permutations

What if characteristics are not nominal?

Special Cases for

(



)

Weighted matrix

Areas become meaningful

Applicable to a data table in which row and column totals are meaningful

Limited in dimension

Matrix-file

When one of the dimensions is too large

Constructed similar to image files

Use sorting to discover correlations

Image File

Used for ordered objects and reorderable characteristics

One card for each characteristic

Values greater than the mean of that row are darkened

Matrix-File

Special case for permutable matrix; one of the dimensions is too big.

Large number of objects across a small number of characteristics.

Constructed similar to image files

Use sorting to discover correlations

Matrix-File Example

Ordered by salary, origin, age

Higher salaries are paid to men, who are married, older and who have more childeren then others

Graphics for Networks

A network portrays the relationships that exists among the elements of a single component .

 can also be represented in matrix form

If this component is

Reorderable: network is transformable on a plane (19)

Ordered: network is transformable on one dimension (20)

Topography: non-transformable; ordered network (21)

Utilization of Synoptic

Using synoptic choose the appropriate graphic construction for your data

Deviating from suggested construction leads to loss of information and requires justification

Size limitations

My favorite Sentence

 “A problem involving n rows does not correspond to n problems involving one row.”

 “[

Graphics ] is a strict and simple system of signs, which anyone can learn to use and which leads to better understanding.”

Contributions

Synoptic

Classification scheme for 2D graphical presentation

Permutation Matrix

General solution for more than 3 variables

(In the book) Identifies seven visual variables

Position,size, value, orientation, color, texture and shape

Texture

Position

Color

Size

Orientation

Value

Shape

References

The book has no reference section!

 Semiology of graphics: Diagrams, networks, maps, J. Bertin, 1967

Identifies basic elements of diagrams

Describes a framework for their design

Critique

 Strength of the paper

One image summerizes his all theory on graphic construction selection

 Weakness of the paper

No 3D discussion

Not easy to follow, lack of examples (in the given section)

Outdated implementation techniques

What happened to this topic?

Formed a basis for research in Information

Visualization

Graphical constructions and ideas presented in this section are implemented in information visualization tools

Tablelens (matrix file)

Spotfire (scatter plots using seven visual variables)

What happened to this topic?

Classification enabled auotomation studies

Automating the design of graphical presentations of relational information, Mackinlay

1987 NSF report, DeFanti (uses the term visualization)

Extension to 3D graphics

Information Animation Applications in the capital markets, Wright

1987 NSF report, DeFanti

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