On Sat, Sep 4, 2010 at 3:09 PM, Xan >>> What is your use case? > Can I choose the three? :-)
No. :-) > What are the technical details of these? Can you give me an sketch. > > My intention was to user has the possibility of choose "layer of things > he/she wants": for example: shops+rivers. And good if he/she could edit the > items displayed in that layer (only shops and river in this example). > > Is it very difficult to do it? It depends on what you mean by display, honestly. > With this OSM act, also, as a service: > - which bus_stop is the nearest of the cemetery of Palma of Mallorca? I > - Wait. Consult OSM and choose "display customized layer" and check > bus_stops and wooala!! only see the map. There's a lot here, so I'm going to stay somewhat high level (read: oversimplified) and also stay pretty close to the use-case level, rather than diving into technical details. Let me start with what I sometimes do for editing. When I'm editing, I often am interested in one or two features. I know the map contains lots of things, but I only want to see things I'm working on. Each editor will do this a bit differently, but Josm and Potlatch 2 offer relatively simple methods to do this. In Josm, it's called Filtering (http://josm.openstreetmap.de/wiki/Help/Dialog/FilterDialog) and in Potlatch 2, you can create a custom MapCSS file with just the items you care about. I mostly use MapCSS to do this kind of filtering. So if that's your use case, that's what you can do. If you're looking to make a custom rendered map, this is a bit more complex. You need to tell the renderer to only represent certain items. The short answer for this is, you have roughly two options. First is to use a commercial service like CloudMade to make your own custom maps, or you can run them yourself. CloudMade has a custom map style editor and then you can make your map the way you want it. You could also make your own service like the one you describe where people could enter their own renders on the fly, but be aware that this is both disk and computationally expensive. OSM doesn't run this type of service, I suspect for a few reasons. One is that, as I mentioned, providing such a service would be both storage and computationally intensive. Doing on the fly renderings like that would place a burden on the system. Secondly, there are options for other providers (including commercial providers) to step in and provide that service for users, if they want/need it. And thirdly, because the data is available, if a user needs that, they could certainly provide it to themselves given a little time and the technical knowhow. Lastly, you mentioned querying. This doesn't sound much like you want a visual representation, but you want to ask geographic questions to the system and get an answer, and I'm afraid I don't know of any service like the one you're talking about, though it wouldn't be very difficult to write. In fact it may exist and I don't know about it, but you could certainly take the data, put it in a database and then run queries against it. I hope that answers your question. - Serge _______________________________________________ newbies mailing list [email protected] http://lists.openstreetmap.org/listinfo/newbies
