Re: [openrailwaymap] Proposal for new Ks signal tagging scheme

Am Montag, 27. Juli 2015, 18:38:17 schrieb Peter Hudec: Just as a preface: I'm not really a railway person. I just have read RL301 and do some tagging. But I'm an IT guy. I do specs and API designs for a living, so I would say I have quite some experience with this. Additionally I have experience with software internationalization and localization. And that is the viewport from what I will mainly answer this proposal. This is just about the tooling, it has little to do with the usefulness of the tagging itself as long as the tagging could be made working. I assume it can, so if the tooling is broken, then fix the tooling, not the tagging. If I look at the signal, there is actually one signal. If I tag it as combined I get 3 possible states: hp0, ks1, and ks2. So the tagging must be: main: hp0;ks1;off distant: hp2;off For any other combination of states we would immediately get situations where both the main as well as the distant aspect are active (ks1+ks2 or things like that). Now you only have to tell everyone that the distant aspect must be off if the main is not off, and vice versa. One could say "this is always the case for signal type DE-ESO:ks", well, ok. But for DE-ESO:hp with main and distant at the same place you have a different (but much more logical) rule: if the main aspect allows passing, the distant aspect is active. If the main aspect is hp0 (i.e. stop), the distant aspect is off. This is logical, since you do not care what the next signals says if you must not pass this one. Let's do it entirely another way: the German signalling system does not allow combined and distant signals at the same position. What happens if any other signalling system allows this (regardless what the meaning of the distant aspect in that case would be)? You can't tag 2 distant aspects without inventing a really weird tagging there. There is main+distant signal in Germany at the same pole: H/V light signals. But those are actually 2 different signals. Everyone can see this. A combined signal is one signal. This tagging says that both hp0 and ks2 are shown at the same time. As Michael already said: this is entirely specific to Germany, even if you give it an English name. Let's say Poland would let the yellow light blink in the same situation. This would give railway:signal:yellow_blink=yes then? And what if yellow blinking light is an entirely different state in Russia? Then you would tag yellow_blink=yes again, and one needs to guess which meaning it has (there are situations where one countries signalling system goes beyond the border for a while). That's why one tags the primary meaning of that things, or a unique thing in states. DE-ESO:kennlicht is unique, and one can easily find out the meaning, as there is only one. marker_light can be different in every signalling system that exists, and it would create more tags that would probably only used in one system. If you want to have a look at such an epic desaster: the tagging for the differnt materials at a recycling point is a pile of yes/no tags, which should have been a simple list instead IMHO. This makes sense, but I fear that it is already too late for this. The other tagging is already out in the wild, and it will be hard to fix this up. There are still new nodes tagged with amenity=fire_hydrant popping up in the database, even if emergency=fire_hydrant is the preferred tagging for years. A simple regular expression allows the opposite already: ([0-9]+ ?)([^ ].*). Probably limited to Ks-Signals, as others are not controlled from ESTW. This is already a badly chosen name IMHO: it should have been states right from the start. Even if it is a sign and can only show one state, but that case can easily be catched. The wiki suggest it should be "distance" without any prefix. No idea why ORM does not use this. This is just renaming without any added value, so you are too late for this. Same as the DR/DB-prefix renaming. Greetings, Eike