In this article I'm going to discuss aesthetic factors which affect diagrams. Readability and beauty are the two most important identifiers of good a diagram. But what makes a diagram more readable and more beautiful? That's what this article is about.
If lines that connect nodes cross each other, it will confuse the reader. So it is very important to have less line crossings as possible. In this article we refer to lines that connect nodes as edges.
The two diagrams below are two drawings of the same diagram but the one on the right is more readable and beautiful because it has no crossings.
It is not beautiful if one part of our diagram is crowded but another part is empty. So it is important to distribute nodes evenly in the diagram space.
The diagram below is a demonstration of a bad node distribution for the same diagram.
An edge is called orthogonal if it is either horizontal or vertical. It is much easier to track orthogonal edges.
The following diagram is an orthogonal drawing of the same diagram.
It is hard to track edges that bend (change direction) a lot. So it is desirable to have less edge bends as possible
Symmetry in a diagram helps understanding the diagram easier. Also symmetry plays an important role in beauty. So try to show as much as symmetry as you can.
It is hard to read a wide and large diagram. So try to make your diagram occupy a reasonable area.
It has been shown that a diagram in which all edge labels are in the same direction is more readable.
In most diagrams edges have directions. when applicable it is more desirable to have all edges flow in the same direction. It is aesthetically more pleasant and easier to read.
If the angle between two edges is small it is confusing. So try to avoid small angles between your edges.
In this article I presented some of most important factors (but not all) in diagram drawing. Sometimes these factors are against each other and usually it is not possible to achieve all. So we have a trade-off between these factors. We should decide which ones are more important for us. but keeping them in mind will help us create more readable and more beautiful diagrams.