How to draw a diagram

A discussion, using examples, of what makes a diagram useful (or not). The talk will also contain pointers on some of the tools I currently prefer to use when drawing diagrams and graphs.

A PDF of the presentation is available here:  http://www.cl.cam.ac.uk/Research/DTG/publications/public/acr31/drawingdiagrams.pdf

Discussion

A large part of the argument presented here is taken from "The Visual Display of Quantitative Information" by Edward Tufte. I strongly recommend this book to anyone interested in further information and thinking about diagrams and graphics.

In the talk I advocate the use of Inkscape for diagram drawing, Gnuplot for drawing graphs and SVG as a common intermediate format for ensuring that your diagrams all look the same. There are of course many other options:

Inkscape	A general drawing tool for vector graphics. It can produce very professional results and is capable of exporting to EPS and PDF. Cool features include bitmap tracing, connectors (which stay connected when you move the boxes they connect), unicode support (for greek letters) and command line invocation for batch rendering. Some things to watch for: sometimes I have trouble using an exported EPS in your LaTeX documents which seems to be something to do with fonts and unicode - you can work round this by choosing export fonts as path when you export to EPS. Also, EPS doesn't support transparency and so if you use these effects in your diagrams they won't come through in the output. I think this is supposed to work with the PDF export but apparently the results are not satisfactory.
Gnuplot	A tool for drawing graphs which can produce SVG file output which you can then (optionally) edit and render in Inkscape. Some more details and tricks with gnuplot are in the HOWTO pages: here
GraphViz	A set of tools to create (topological) graphs from simple text-file descriptions of the nodes and edges. The tool will automatically try to lay out the graph in as neat a fashion as it can. There are five or so built-in layout styles, the most popular of which is called dot. Can export graphs as SVG, PNG, EPS, etc. Unfortunately, there is no way of manually editing the graph after layout, so it's hard to apply minor manual tweaks. See more at  the GraphViz website, or take a look at the helpful  dot user guide. For embedding GraphViz graphs into LaTeX documents, use  Ladot to allow LaTeX formatting to be used on node and edge captions.