Create UML diagrams, FlowCharts, Network diagrams, to EPS, SVG, PNG, with Dia

Dia is a GTK+ based diagram creation program inspired by Microsoft Visio, though more geared towards informal diagrams for casual use.

It currently has special objects to help draw entity relationship diagrams, UML diagrams, flowcharts, network diagrams, and many other diagrams.

It is also possible to add support for new shapes by writing simple XML files, using a subset of SVG to draw the shape.

It can load and save diagrams to a custom XML format (gzipped by default, to save space), can export diagrams to a number of formats, including EPS, SVG, XFIG, WMF and PNG, and can print diagrams (including ones that span multiple pages).