Hi Martin, Am 2016-10-05 um 10:13 schrieb Martin Koppenhoefer: > 2016-10-04 21:36 GMT+02:00 Michael Reichert <naka...@gmx.net>: >> https://wiki.openstreetmap.org/wiki/File:Station-asymmetric.svg >> >> (1) A passenger might define the station as the area around the >> platforms, the station building, and – that's another dispute – maybe in >> addition the bus stop and car parking. This is shown as the purple thick >> line. >> > > > > if I understood your sketch "simple station" correctly, you see > public_transport=station as a way of representing this, right? Anyway, with > an extensively mapped station, a passenger could find out "his version of > the station" by looking at all accessible footways/highways and platforms > inside the station area.
Yes. >> (2) Train staff and other people interested in railway operations have a >> much larger definition of the station. It includes the whole siding and >> yard tracks which belong to the station. Depending on the country, a >> station begins either at the entry signal (left outermost signal in >> the image) or at the first point a train passes when it enters the >> station. The station ends either at the entry signal of the opposite >> direction (right outermost signal in the image) or the last point a >> train passes which leaves the station towards the right edge of the >> image. This is shown as the thin rose line. >> > > > this is what I would use for railway=station. I guess "point" was meant to > be "switch point"? Yes. > I would prefer "switch point" for the limit along the > tracks, because this is easy to spot on aerial imagery, easy to map, > logical because outside of the first switch you are likely on a track meant > to go somewhere, rather than a less important track inside the station. I > wouldn't oppose "entry signal" neither, and I guess there is not so a big > difference between the 2 variants. It wouldn't actually matter for my > mapping and to get an idea how big the station is (I think, feel free to > tell me more). There are usually a few hundred meters left between the first point and the entry signal. It is used for shunting movements inside the station (i.e. an engine which is moved from one track to another) and a safety distance to prevent collisions between shunting movements and a train overruns the entry signal if it displays the stop aspect. Wether the stations ends at the entry signals or at the last point depends on the country. It is ok and the way how OSM works if a mapper only maps the area from first to last point if he cannot spot the entry signals on the aerial imagery (either because they are hidden by trees or do not exist or he is not a railway mapper). >> I think that we should use the established tag railway=station for nodes >> only because the node will located where everyone agrees that there is a >> station. If we tag (2) with railway=station, the centroid of the area >> will be at a position where users would not expect it – neither >> passenger nor railway staff. >> > > > If you think you will need an extra node or more, call it > station_access_point or something similar (btw. there is a suggestion in > the wiki to call all these railway=subway_entrance, not my favorite term > actually, because of the word "subway"). This simple idea of putting > floating nodes has serious limitations anyway in all cases where the > station is more complex (e.g. access from both ends). From a logical point > of view, it makes not sense that "railway=station" represents something > different than a railway station, and railway stations do have significant > spatial extent. The problem is that railway=station has the meaning "train station for passengers (and goods in addition)" and has been mainly used for nodes. Therefore data users who render maps, usually calculate a centroid and place an icon there. If we start mapping definition 2 of a train station as an area with railway=station, these data users have to change their map styles. Icons will get rendered at wrong locations. Search engines will return wrong results. https://umap.openstreetmap.fr/de/map/unbenannte-karte_105529#9/49.2597/9.5004 shows some assymetric stations. Albtalbahnhof (the stations where light rail services to Rastatt and Ettlingen depart) is a train station whose platforms and station building is located at the northern end of the station. Mapping an area with railway=station, will harm most data users. My suggestion: Use railway=station + name=<name of the station> only on one single node. Use public_transport=station + name=<name of the station> on areas which cover the station building, platforms and other features important for passengers. Use an area with railway=station_extend + area=yes + name=<name of the station> to map the extend. Drop the relation (type=railway) I suggested in an earlier posting. https://wiki.openstreetmap.org/wiki/File:Railway-station-extend.svg Shall I write a tagging proposal? Best regards Michael -- Per E-Mail kommuniziere ich bevorzugt GPG-verschlüsselt. (Mailinglisten ausgenommen) I prefer GPG encryption of emails. (does not apply on mailing lists)
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