Create Flow Chart, UML Diagrams (class diagrams, sequence diagrams etc.), Network Diagrams, Entity Relationship Diagrams and more with the free visio alternative called Dia.This free diagram software was inspired by Visio and is a good alternative to the Microsoft program.
Dia has a lot of pre-defined shapes that makes it easy to draw the network diagrams, UML diagrams and more. It is also possible to add support for new shapes by writing simple XML files, using a subset of SVG to draw the shape.
Dia depends heavily on a menu on the right mouse button inside the diagram. That menu contains all the diagram-specific actions and a few other things, so you almost never have to find the menu on the toolbox. You can change to a “normal” menu bar in the Preferences dialog. However, this will only affect diagrams opened after the preferences are changed.
Dia can not only load and save diagrams to a custom XML format, which is gzipped by default, it can also export diagrams to a number of formats, including EPS, SVG, XFIG, WMF, PNG, PDF and many more. It can also print diagrams including ones that span multiple pages.
If you don’t have a middle mouse button, hold down the Ctrl key and use the right mouse button in windows. In Linux, you can make a middle-button click by pressing both buttons simultaneously.
Here is a sample UML Diagram (Class Diagram) drawn with this free diagram software.
Here is a snapshot of network diagrams that can be drawn with Dia.
Dia works on Windows 7, Windows Vista, Windows XP and Windows 2000. It requires the GTK+ Runtime Environment version 2.10 or higher (included in the installer).
Free download Dia for Windows from here and enjoy the free diagram tool.