dia: Dia dia: dia: Dia is a GNU program designed to be much like the Windows program dia: 'Visio'. It can be used to draw different kind of diagrams. dia: dia: It can be used to draw a variety of diagram types, including UML, dia: Network, flowchart and others. The native file format for Dia is XML dia: (optionally gzip compressed). It has print support, and can export to dia: a number of formats such as EPS, SVG, CGM and PNG. dia: dia: