Hi, Am 01/06/2020 um 14.08 schrieb Rolf Eike Beer: > Am Montag, 1. Juni 2020, 11:13:54 CEST schrieb Rainer: >> Hi Maarten, >> >> I agree that the tags railway:pzb, railway:etcs etc. are chosen >> awkwardly. The tag should express that these are train control systems; >> now with railway:pzb=* you have to know that pzb is a train control >> system. If somewhere in the world the system xyz is added, it is not >> recognisable from the tag as train protection. >> Therefore I suggest to change railway:pzb|etcs|lzb|atc|...=yes|no into >> railway:train_protection:pzb|etcs|lzb|atc|...=yes|no . This would >> provide more clarity and make it possible to actively set a >> railway:train_protection=no to express that no train protection system >> exists and to distinguish it from the lack of information. > > How about > > railway:train_protection=pzb;lzb;etcs > railway:train_protection:etcs:level=2 > > That would be only _one_ key to check. > > We had this discussion years ago, but I don't remember the outcome anymore.
There was no real discussion. It was a GitHub ticket and an email by myself on 27 November 2014 asking for comments but I did not get any. https://lists.openrailwaymap.org/mailman3/hyperkitty/list/[email protected]/thread/6IOOVCKWBJ3CPOQK7LP2OJIQEMUVB5JU/ The current system of tagging train protection is designed in a bad way in two aspects: 1. We have one key per train protection system. As long as a map style developer knows all train protection systems (i.e. a map limited on Germany and Austria), this works. Current display of train protection is, as documented in https://github.com/OpenRailwayMap/OpenRailwayMap/issues/64#issuecomment-154743215, still a temporary, Germany centric solution. :-( However, there is a large number of different train protection systems in use all over the world. In order to render a true "no train protection here", a special "there is no train protection here" tag is required because a map style developer cannot have knowledge of all train protection systems. A tag such as railway:train_protection=no as Rainer suggested, would fix that. 2. Using one key per train protection system is not a good design. It requires a style developer to know all keys used for train protection systems. This does not scale well. If we used an unlimited number of keys with a common prefix as suggested by Rainer, it would counteract the idea of a key-value based systems where keys are used to query their values. Back in 2014, I suggest to use a limited number of keys only (about three or four) where each key would represent one level of safety. However, it introduces duplication and stores the safety level of a system in OSM. I doubt that people might disagree on the safety level of a certain train protection system and therefore agree with Eike's simple (and therefore OSM-like) solution for the problem. Best regards Michael
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