On 25/11/2009, at 14.11, Jean-Marc Liotier wrote: > Ævar Arnfjörð Bjarmason's diary entry last week (http://j.mp/8ESP8o) > stired my interest. Using a few examples, he showed how mapping > everything as an area - or as a volume - makes ultimate sense. > Should we > go for it now ?
Talking about roads: I don't see the point mapping roads as areas. There's not much you do with an area that can't in principle be done using a line with appropriate tagging. The problem is that the current tagging namespace is too simple and not expressive enough to allow it. For example, if I write highway=residential cycleway=track width=3 there's no way for you to know if "width=3" describes the cycleway or the road itself. In my view it would make much more sense to work on a more expressive (perhaps BNF based?) tagging scheme. This would enable a gradual enhancement of the map, where the new tagging syntax could live along-side the old. Areas are reminicent of the "map-drawing" approach to the map, in the sense that mankind has been drawing maps with paper and pencil for thousands of years. The "map-drawing approach" is valuable in OSM because it allows us to indicate residential areas parks, etc. However, in addition, OSM has a graph-based approach for a description of the network of roads which makes it *uniquely* valuable. Graphs prefectly represents the road map and can be used for many applications, routing is an example that many people use daily. Conversely, there isn't much you can do with graphs that can't be done with areas, and since the "map-drawing" approach has great appeal to people enjoying beautiful and detailed maps, the pressure for deprecating the graph-based approach in favour of the map-drawing approach will be ever increasing. We need to resist that. Let's not throw out the baby with the bath- water! Cheers, Morten _______________________________________________ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
