[pjtr]

I'm missing where they are sorted by x-y values.

I did a quick and dirty experiment: http://pastebin.com/NjZNRjw1

Seems about 30% smaller than before on http://i.imgur.com/5zwCEF5.png

[ruarai]

Wow, that works pretty well. I was mistaken in thinking that either the Dictionary class or the process of sampling would sort them.

Mind if I merge that? Or you could submit a pull request. Either would be great!

Also, do you know of any resources for learning about how to optimise for gzip compression? Google is just telling me about compression for websites.

[pjtr]

Sure, feel free to merge.

I don't know any resources specifically about gzip compression. Demosceners have very practical and fun compression know how, so maybe look into: http://www.farbrausch.com/~fg/seminars/workcompression.html

[willvarfar]

Compression gurus hang out at http://encode.ru

You'll likely find a compressor much more suited to your particular data than gzip.