Hamburg public transport (HVV) shows two variants on relations for subway/lightrail lines splitting into a "Y" (three endpoints):
Maybe there is subtle differentiation here (which I don't see) on how these trains serve the alternative endpoints by splitting (front/back) at Ohlsdorf/Volksdorf or alternating full trains serving alterative routes (S1 splits in Ohlsdorf), but I would like to understand the reasoning behind mapping S1 as two fully parallel lines starting in Wedel (four relations) and U1 having one main line until Volksdorf plus two connecting lines (six relations). Both variants show up very differently in Overpass (U1 S1). I would consider S1 Overpass the correct way to display such a Y-line. But I'm not sure if the difference in relation-style explains this and needs to be fixed. asked 25 May '20, 07:59 Aeroid |
The graphical representation with Overpass seems to be misleading. Have a look at these alternative graphs: S1, U1. You can switch on/off the individual branches through the menu under the "LS" button on the top right. Both ways of mapping are used. I tend to follow the S1 way and I think that is what is mostly done in my local Verkehrsverbund but the U1 way is quicker to do as you don't have to repeat everything for the common section. As long as we don't have timetable information in our data it doesn't really matter which way is followed. answered 25 May '20, 08:46 TZorn Thanks, but I guess the 6-relation-variant (U1) has the general disadvantage of not differentiating between the two "leaves" and the "trunk". That Overpass chooses the "joint" as a starting point out of the four options is certainly the worse case, which S1 avoids by not offering the "joint" as an end point.
(25 May '20, 10:16)
Aeroid
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