Graph drawings are used to represent relationships between objects in the form of arcs and nodes. Aesthetics and secondary notations are two influencing factors in designing the layout of information in graph drawings.
Aesthetics refer to the criteria that concern graphic aspects of readability.
Examples of aesthetics include the number of bent arcs and the flow consistency of the graph drawing. Secondary notation is defined as additional information added to diagrams that may assist in conveying information, for example, adjacency and labelling. UML uses varying forms of graph drawings that graphically express designs to enable communication between customers, users, developers and other persons involved in the software engineering process. Use of appropriate aesthetics and secondary notations may assist in presenting information clearly and unambiguously. Aesthetics and secondary notations also need to be assessed to determine which factors influence users' performance.