This question reminds me of the work Microsoft Research developed to automatically create 'hand drawn' maps for Bing. The process relies on four steps: data selection, data simplication, layout and decoration. The tool seems to be offline now, but when I tried it, it worked well for simple direction sets, but like the charts problem, it sometimes needed human curation to ensure that the selection and simplification steps were meaningful.

Details: http://research.microsoft.com/en-us/news/features/destinatio...

Example: http://research.microsoft.com/en-us/um/people/kopf/destinati...