Re: [openrailwaymap] DE: Optimale Position von railway:switch-Nodes u.a. / EN: optimum position of railway:switch nodes etc.

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 Hi Denis, Am 19.09.2016 um 19:02 schrieb Denis Stein: In history, mappers usually mapped the point at the common crossing or a location between the point blades and the common crossing because the common crossing is better visible on aerial imagery. You have to have a little bit more understanding of railways than Joe Average-Mapper and need very good aerial imagery to spot the point machines on Bing imagery. I myself move all the points I find during mapping to the tip of the point blades because that's the location where the track centerlines split up. Diamond crossings are mapped where the track centerlines intersect. If they are mapped differently, e.g. like this \ / \ / \ / / \ / \ / \ (a common piece of track, looks like two points), they have been mapped long ago when only worse Bing or Yahoo imagery was available. Did you mean a "Doppelweiche" (the blades of the second point are between the point blades and the common crossing of the first point)? http://www.tf-ausbildung.de/BahnInfo/dw.htm This should be mapped as two single points. I prefer to map single and double slips like diamond crossings but with special tags. If we want to map the possible turnout directions of single slips, I would use turn restriction relations as used on roads. Routing engines have been supporting turn restrictions for many years. To reduce the number of turn restrictions which have to have mapped, I would not map a relations if it is just the opposite of another turn restriction on that point (i.e. copy of another relation but from and to members are switched). While writing a routing engine for trains becomes easier if we map single/double slips as simple points, rendering a nice map (especially track layout diagrams becomes more difficult) becomes more difficult. There are several OSM-based routing engines which already support turn restrictions but there is no software which simplifies double slip points mapped in a way you propose. (In general, cartographic generalization of geospatial data beyond a simplification of the geometry is more difficult than parsing turn restrictions) 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)