On 13.04.2013 08:11, Martin Atkins wrote: > http://wiki.openstreetmap.org/wiki/Proposed_features/Railway_Schematic_Mapping
You are touching a tricky issue with a proposal that is honest about its limitations, so I welcome the constructive input. But unfortunately, I doubt it is the right way to go. First, lets compare this to highway: There we map separate highway ways when there is a physical separation, e.g. with dual-carriageway motorways. This is not the same as lanes, where you may often change lanes at any time e.g. for overtaking, and could often move to any lane even if you are not allowed to. Between railway tracks, there is *always* some physical separation - you cannot just move to a parallel track. So it is not true that your proposal would be required to maintain consistency with highways. Applying a "lanes" tagging scheme to railway would just highlight its limitations: Even with highways, we don't have any established solution for transitions between way segments with different lane layouts yet. As you admit in your proposal, this means that we would, for example, lose our current ability to to easily and intuitively map railway switches. There would many similar unsolved issues regarding accuracy, many of which you actually point out yourself, too (such as the 90° turns at intersections). But I think not all mappers would agree with your judgement that this very generalized mapping is good enough. Too much important detail is "left as an exercise for someone else who is interested". Therefore, it is not surprising that mapping of individual tracks tends to dominate in well-mapped areas with decent aerial imagery. At least in the areas I'm familiar with, drawing parallel railways as a single way is mostly limited to two cases: * early mapping (sometimes even GPS based), to be improved later * trams, as the unsolved rendering issues are particularly obvious there To sum this up: I'm aware that we have unsolved problems with our railway mapping scheme, and that it is hard to serve the needs of many different use cases at once. But your proposal feels like giving up and focusing exclusively on a generalized, road-centric map, and we should strive for more than that. Tobias _______________________________________________ Tagging mailing list [email protected] http://lists.openstreetmap.org/listinfo/tagging
