On Wed, Jan 30, 2019 at 02:44:50PM +0100, Tobias Zwick wrote: > I stumbled upon a real-world example yesterday that may make the attempt > to have the level-tag describe a "global" order (as used in OpenLevelUp, > JOSM etc.) somewhat impractical - with that level-selector UI element: > > So, Hamburg is a really flat city. And even still, the mall "Europa > Passage" ... > https://www.openstreetmap.org/way/214840502#map=17/53.55223/9.99644 > ... does have two "ground floors". If you enter through the northern > entrance, you are in the lower ground floor (level=0), if you enter > through the southern entrance, you are in the upper ground floor > (level=1). If you walk alongside the mall though (Bergstraße), there is > no (apparent) elevation. > > So, imagine there are more indoor-mapped places both around the northern > and the southern end of that mall (there is, partly, but I am sparing > you the details), and as a matter of fact, sprinkled throughout the > entire city centre. > Then, to have a global order of things, the ground floor of all the > buildings South of that mall would need to be tagged with level=1 and > the ground floor of all the buildings North of this mall would need to > be tagged with level=0. In other words, must be relative to the level > order used in this building. > > I see two problems with this: > > 1. Where to stop? How global is this global order? Going further South, > at what point does the level-value for the ground floor revert back to > 0? What then if two such places collide? (A mall and a multi-level train > station were mapped separately and they built a tunnel to connect the > two, but they connect on different level=X - or not even a tunnel, let's > say they are just next to each other)
The level value is only valid inside one building in my interpretation. The safest value to join ways from different buildings would be using key:ele. Often enough there will be problems of the kind that a level value isn't even uniformly valid inside one building. Richard _______________________________________________ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
