Visual languages: concepts, constructs and claims

Historically (1984) a group of researchers at Hiroshima University, Japan, considered how to bridge the chasm between high level programming languages and the human level by introducing a purely graphical language (called visual) which would be able to express both data and control structures so that real programs could be drawn. This basic idea stemmed from a natural extension of the direct manipulation interface where icons are selected, dragged and placed near/on top of other icons so as to express actions that may entail processes of variable complexity. The concept of usability, in terms of human acceptance and satisfaction of the visual language, was introduced so as to enable a human-centered evaluation of the implemented prototypes. At the same time, research has also considered graphical layout on the screen, a number of different visualization strategies, the user task analysis, user modeling, icon design according to different user cultures and background, a definition of state within an interactive system, and many others as may be seen by the growing number of meetings on all these subjects. The paper discusses the concepts and claims of visual languages.