NetDraw

NetDraw is a free program written by Steve Borgatti for visualizing both 1-mode and 2-mode social network data. It can handle multiple relations at the same time, and can use node attributes to set colors, shapes, and sizes of nodes. Pictures can be saved in metafile, jpg, gif and bitmap formats. The program reads UCINET system files, UCINET DL files, Pajek files, and its own VNA format (which allows saving network and attribute data together, along with layout information like spatial coordinates, colors, etc.). IMPORTANT: If you format data as a VNA file, NETDRAW can handle *very* large files. For example, sparse networks of 3500 nodes are very practical on a machine with 1GB of RAM (more is better). 10,000 nodes works fine with 2GB of RAM (assuming it is very sparse, of course).