Display Models - ways to classify visual representations

Visualizations are generated of diverse data and use many different techniques and visual methods. It is often beneficial to evaluate what is being visualized and how the visualization is made-up. Such an analysis may aid the developer, to understand what `tools' are available, and help the user to reference and compare different realizations. Display models specifically classify the data by what type of output can be created. We review many `display oriented models' and discuss important aspects of these methods and ideas. In presenting these models we encourage their use. In particular we focus on the symbolic reference model of Jacques Bertin. He used this model to describe images and 2D visualizations. We translate Bertin's scheme into an algebraic form as a method to describe visualizations.