Thanks! The GitHub project is still available but is many years out of date now. I did this when vector tiles were new, there's now really good software packages out there. Some of the ideas of cleaning and simplifying the data may still be useful though.

https://github.com/NelsonMinar/vector-river-map

I agree.

@GP: It's never too late to post old stuff in HN if it's interesting. Just add (2013) to the title here. It can also be a post mortem, with the extendd story in your comment, a few maps and the explanations of the main suggested improvements.