On Saturday 04 May 2019, Tobias Knerr wrote: > > Here's the raw data if you'd like to examine it: > http://tobias-knerr.de/upload/Step%20Polygon%203D%20Examples/ > Please excuse the sloppy mapping, those are just intended as tests.
Thanks. I guess that means your approach relies on a one-to-one relationship between linear ways and polygons - or at least on the polygon outline being intersected by the linear ways exactly twice. > While you correctly point out several further limitations, I think > it's important to keep in mind that this isn't an attempt to define a > data model that works for everything. It's about finding a sweet spot > that works for a sufficiently large class of steps to be worth it and > is still relatively simple. What would likely happen with your approach is once there are data users using it mappers would start splitting any stairs that are not supported by the algorithm artificially into parts small and simple enough for the algorithm to deal with and you'd end up with data modeled for the specific requirements and limitations of the algorithm rather than for mapping-efficient documentation of the nature of the stairs. > As for that data model that works for (almost) everything, I believe > that will have to be drawing a way across the edge of each step. > [...] That would essentially be giving up on mapping the stairs as an overall feature and modeling the steps individually instead. For data users that need only individual steps in the end anyway this would be convenient but for any data users who want to interpret the steps as a whole this is a bad idea - likewise for the mapper who does not want to mechanically draw step after step. Circular concentric steps for example like this: https://www.designdiffusion.com/en/2018/10/15/japan-plaza-cofufun-designed-by-nendo-for-the-local-community/ you could model with: * one circular way per step. * a number of sector polygons and centerline ways suitable for your algorithm. * a single node and tags for step count, height, inner radius and outer radius. -- Christoph Hormann http://www.imagico.de/ _______________________________________________ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
