Prompted by the recent release of the trading funds report (http://www.freeourdata.org.uk/blog/?p=180), I was dreaming about what might happen if the Ordnance Survey suddenly decided to make their data freely available. How would we integrate it with the main map?
We've had this problem on a smaller scale with TIGER/LINE. As I understand it, the data was simply uploaded into the main map, and then any areas where mapping had already been done were resolved and de-duplicated by hand. Is that correct? It seems to me that it might be much better to start having the concept of multiple layers in the OSM DB. So one could upload a large contributed data set to a new layer, and then merge the two together slowly. But, and this is the key point, during the process things like the slippy map would just render the "main" layer - thus avoiding an extended period of time where the map was unusable due to lots of things being on there twice. Clearly, this would require a tweak or two to the DB (a "layer" value for each object), the API (you'd need a way to request non-default layers for a particular bbox) and e.g. JOSM (although it already has the concept of different layers of OSM data). But I think it would help us a great deal. As OSM gets better, it's much more likely that data donations will cover areas where work has already been done. Having a good way to merge the two while keeping the map usable during the process is, it seems to me, important. What do people think? Gerv _______________________________________________ dev mailing list [email protected] http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/dev
