> On Nov 13, 2019, at 3:44 AM, Richard <ricoz....@gmail.com> wrote: > > We need new tags for the bottom of embankmets, top of cuttings, bottom of > cliffs, earth_banks > and maybe a few others if we want to map them.
that is very true. I think we can cleanly do this with the ways you mentioned. We need to chose a scheme for these “base” tags that doesn’t reinvent the wheel, isn’t vague, and can easily be interpreted. my mis-reading of embankment led to some big problems, simply because I assumed the tag could document things it couldn’t. Your tags look really good to me. > On Nov 11, 2019, at 6:15 PM, Martin Koppenhoefer <dieterdre...@gmail.com> > wrote: > A relation seems easier to evaluate and explicit, while a spatial query > heuristic will inevitably fail in some cases I think there is a need for a basic relation, if I understand Martin correctly, to simply associate the two lines, (for example, an =embankment and an =embankment_base pair). When mapped, they are not joined. They are merely adjacent. I am not sure of what “type” of relation to choose in iD, but I assume someone will tell us which type to use. When mapping a simple cutting or embankment, you would have only one “base” line adjacent - so there is little ambiguity, and the relationship can be inferred (IIUC), but in complicated tagging, there could easily be a situation where which base belongs to which line is unclear, and lead to problems. Simply putting them into a relation says “these members are related” and the renderer can know for certain that these two ways that don’t share nodes are a pair, no inference needed. This again raises the question of levees - is the levee worthy of it’s own levee relation? do you put all 4 embankment lines into relation with the man_made=dyke line? this seems to be the only solution to: - properly group the embankments with the levee - not have to use super=relations (putting the embankment relations into a levee relation) - providing the most flexibility to weird situations - allowing for the extent of the top of the levee to be defined (large levees have varying width tops with usable areas, as shown, in which a “way” is insufficient ). But I am unsure that this is the “only way” and perhaps putting the two embankment relations + dyke line into a levee super-relation would allow mapping of the embankments to be a uniform process (making mapping the details of levees a bit more complicated at the expense of standardized embankment mapping). Javbw _______________________________________________ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
