Robertson & De Ferrari

Systematic approaches to visualization:
is a reference model needed ?

This text is partially taken from [ROB94]

A reference model is a general visualization model

1. to show an abstract description of the visualization process
2. to describe the components
3. which is independent from
   
   • paradigms, and
   • data to represent

"The lack of a clear reference model, within which the scope and limitations of existing tools and systems can be identified, makes it difficult to design improved approaches in a systematic manner. The task of generating robust default visualizations of data under exploratory or directed investigation, or automating the production of such defaults and assisting the user to refine them, relies on having 'standard' representations that satisfy established or specified criteria for interpretation. This task also points to the need for a reference model that is formalized."

Robertson and DeFerrari describe six components of a visualization system that define its quality: data model, visualization specification, visualization representation, matching procedure, visualization display and interaction.

An integrated visualization model [ROB94]

Data model:

• support for multiple data set (set with any number of variables, variables with any number of dimension)
• easy and efficient support for implicitly- (e.g. image) and explicitly-gridded data (numerical data)
• support for describing relations between data variables
• support for storing information about missing data variables
• included information about sampling, upper and lower bounds of values, co-ordinate systems, scale and continuity of data.

Visualization specification:

Two main forms:

1. user directives (e.g. don't show variable X)
2. interpretation aims (e.g. show local trends for variable X)

Visualization representation:

A formalism to subscribe the characteristics of many possible visual representations.

Matching procedure:

Given are the three components (1-3):

1. data described according to the data model
2. visualization specification (user directives, interpretation aims)
3. formal description of available representations

Find a displayable visualization in consideration of these three components

Visualization display

A visualization representation device

Interaction

• Changing a parameter without changing the visualization system.
• Make connections between data variables and parameters of the simulation model, and the visualization specification.

Visualization Concepts

Last modified on February 11, 1999, G. Scott Owen, owen@siggraph.org