Dia is a vector-based drawing tool similar to Win32 OS Visio. It is suitable for graphical languages such as dataflow diagrams, entity-relationship diagrams, organisation flow
charts, universal modelling language (UML) diagrams, electronic circuit diagrams and much more. It is ideal when the diagram has shapes that recur and are connected by lines.
Dia is extensible through the use of sheets which contain collections of shapes for use in diagrams. The ER sheet, for example, has shapes for different types of entities, attributes and relationships as required when drawing entity-relationship diagrams for database design.
Dia also runs under Win32 OS (see http://hans.breuer.org/dia) providing a free cross platform tool. Storing it's diagrams natively as XML documents means that they are accessible on multiple platforms and from other applications. You could even edit the dia XML diagrams by hand. Some applications also generate dia diagrams.
In this chapter we begin with some basics and then a walkthrough that should get you started with dia. We then review the functionality of dia. And we end with a walkthrough creating your own shape library.