[Mostly inspired to say this in public after Harry's recent entry, and some of the comments that followed.]

The poor Latin aside, one of my side interests is public transport. Having ridden many of the area's bus routes, and induced paranoia in drivers on others (mostly through tailing them in the car), I have built up a sizable amount of route data for this part of the world I call home. Indeed, a look around the last edition of ⍰PNV-Karte, and a good deal of that red is my fault. Therefore it seems quite a shame to have seen said ¿PNV-Karte fall into the trouble it has - particularly given it was a very useful tool for mappers to check their data against once the updates had gone through.

I have a small render (based on this) set up on a VM at home to simply draw red lines on transparent tiles for pretty much the area you see there, and little else. (I don't have the space or the processing power to do much more - it can do this basic download-filter-render cycle in around 90 minutes).

There are some hurdles I'd need to overcome to push this further, and some things I'd like to explore once over the hurdles.

Hurdle 1: resource. This very plainly isn't going to scale to anywhere beyond the slightly-less-than-a-square-degree I currently have on my box at home. I can't get past transparency because I suspect the VM won't handle the coastline, etc. (which I dropped from the local render - no great loss if they're transparent). Such a thing is also of no use to anyone if it's buried at home without a permanent connection.

Hurdle 2: stylesheets. Mapnik stylesheets appear to be a pain in the bum to maintain. Indeed, a look at the 270kB monstrosity that powers the main Slippy Map would leave me surprised if the policy was anything other than "If it's working, leave it the fuck alone". Generating the simple plain red semi-transparent lines (which look kind of awesome when they've built up with lots of routes, but could be better) was nice and simple with the use of Spreadnik, but anything more complex is going to be awkward, but not necessarily difficult.

With the hurdles dealt with:

1. Get lines and numbers on the map. Maybe use shields in certain views. For local networks, maybe use dynamic colouring - the base colour of a line (or better still, the background colour for the shield) comes from the color attribute on the relation.

2. Go well beyond transparency. Produce maps at tighter zooms that look like some city plans - grey background, white roads, colour fill for streets used by buses. Turn one a Mapnik feature to my advantage by maybe using different styles for z11-14 and z15-18 (Or Something[TM]).

Anyone up for some aerial baking?