Figured out a polynomial to make the lines scale intuitively (oddly enough they need to start thick, get thinner, then get thicker again as you go from zoomed right out to zoomed right in). I have colours working for feature categories (although the actual colours will almost inevitably get changed). Still haven't worked on point display yet. I've also figured out how to detect the features under a click, so it'll be easy to decide which one deserves the click based on the extent and type of their geometry. Coming along nicely.