OpenStreetMap
La Défense, France - what goals should I set for multi-level complications ?
Posted by Jean-Marc Liotier on 25 November 2009 in English.My part of town in Paris, France is called La Défense and it is a complicated layer cake of all sort of tunnels, galleries, multi-level motorway interchanges, public transportation, maze-like passages around and across buildings and pedestrian plazas. I'm beginning to improve it, but as I'm a beginner at the art of mapping, I find it daunting. I wonder what my goals should be. For now, OpenStreetMap does not model volumes but thanks to layers, the map is not quite flat either. But should I even attempt to map this complicated multi-level underground network entirely, or should I focus on the roads and on the surface network ? Is there a best practice somewhere, showing what level of detail should be aimed for ?
Discussion
Comment from dmuecke on 25 November 2009 at 17:15
Maybe Japanese mapper can help you. Mapping Tokyo must be similar.
Comment from Baloo Uriza on 25 November 2009 at 20:14
Definitely start with the most obvious features first, like the primary, secondary and tertiary grids and well-known landmarks. Then start down the residential stuff. Then go for addresses, postboxes, smaller landmarks, etc.
Comment from plush on 27 November 2009 at 06:22
La Défense is truly unique with its crazy maze of passages. This is a long-term challenge that will keep you and probably many other mappers busy for a long time...
I would say start with what is most important - the RER and metro stations, the motorways, the main pedestrian routes on the surface and any landmark buildings such as the Grande Arche or CNIT. After that, the more passages you add, the better.
Unfortunately, neither JOSM nor Potlach is designed to handle such vertical complexity. It will be very hard for you as the cartographer and for any map user to keep track of what crosses what at what level... but that is how La Défense was designed - not our fault.
Thanks for tackling this area. The next time I am in Paris, I sure will be glad to have good maps of La Défense available.
Comment from Jean-Marc Liotier on 27 November 2009 at 10:47
I'm taking it slow, improving gradually what is already there. Landmark buildings with names and height and surface ways for starters.
On top of the vertical complexity, the lower levels pose a data-gathering challenge : they don't appear on satellite imagery, GPS is useless there and I don't have a decent inertial navigation system at hand... I hope I'll find source material with an accommodating license. Maybe I'll ask EPAD - the semi-public organism in charge of managing La Défense.
Comment from Jonathan-David SCHRODER on 28 November 2009 at 04:37
Hello Jean-Marc,
what name/syntax do you give to your layers ?
I'd like to draw indoor stuff with different floors and would be glad working with you. my skype is myselfhimself if you want and I study in Paris.
Comment from Jonathan-David SCHRODER on 28 November 2009 at 04:43
Ok I see that you used the tag : layer=INTEGER
how do you manage to display filter that layer tag out in an osm client ?