There has been a great interest recently in systems that use graphics to aid in the programming, debugging, and understanding of computer systems. The terms "Visual Programming" and "Program Visualization" have been applied to these systems. This paper attempts to provide more meaning to these terms by giving precise definitions, and then surveys a number of systems that can be classified as providing Visual Programming or Program Visualization. These systems are organized by classifying them into three different taxonomies.

[...] we must find ways to make the programming task more accessible to users. One approach to this problem is to investigate the use of graphics as the programming language. This has been called "Visual Programming" or "Graphical Programming." Some Visual Programming systems have successfully demonstrated that non-programmers can create fairly complex programs with little training [3].
Another class of systems try to make programs more understandable by using graphics to illustrate the programs after they have been created. These are called "Program Visualization" systems and are usually used during debugging or when teaching students how to program.
This paper, which is updated and revised from [4] and [5], attempts to provide a more formal definition of these terms, and discusses why graphical techniques are appropriate for use with programming. Then, the various approaches to Visual Programming and Program Visual zation are illustrated through a survey of relevant systems. This survey is organized around three taxonomies. Finally, some general problems and areas for further research are addressed