This weekend AJ and I participated in Mapnik's Committers and Cartographers sprint at CloudMade's office in London. It has been quite an experience with an impressive group of developers, OpenStreetMap board members, and cutting-edge map creators (like the makers of OpenCycleMap) taking part.
A lot of great work got done over the weekend. Mapnik now caches features from shapefiles for repeated occurrences in maps, better handles reprojection with threads, and can input WKT data directly into Mapnik for display. Additionally lot was done to advance Mapnik2, write better documentation of the Mapnik mapping toolkit, and improve performance.
There were some excellent discussions and demonstrations. Steve Chilton presented his documentation of hard rendering problems he's found from building the global OpenStreetMap style, Ivan Sanchez rewrote Spreadnik, his software for creating map styles from OpenOffice spreadsheets, and we showed off TileMill, StyleWriter, and TileLive.
There was also great energy, with Dane Springmeyer just returning from FOSS4G with details on Mapnik's excellent showing at the WMS shootout with paleoserver and everyone is excited about MapQuest switching to Mapnik and publishing their stylesheets. The work on Mapnik happening now will make it easier to create great maps. Already there are changes within Mapnik2 that make some of AJ's work, like the World-Glass tileset, possible to create without lots of post-processing and special knowledge.
Everyone split up yesterday with folks headed back to Germany, Spain, the United States and elsewhere, but we are all excited to continue this work. You can join the conversation in the #mapnik room on IRC.