[Tagging] Feature Proposal - RFC - window:shape

[stevea]

A rather fundamental tenet of OSM is that we tag "what is" rather than (at least in the case of windows), "what we can see."  I mean, most of time, tag what you see.  For windows, if you KNOW they are double- or triple-glazed, add that fact as a datum, if not, omit it.  Generalize that to be "if you know it, tag it, if you don't, don't."

OSM models the real world, not how it looks or for any particular renderer.  Be a generalist about "what is," rather than specify (especially being TOO specific) about what a renderer might want to "see" as a tag.

Regarding curves:  yes, curves are built as a way, where "calculus" determines how smooth the curve is.  More nodes, more faithfulness to the shape.  But we can't enter an infinite number of nodes to get a perfectly smooth curve.  "Enough is enough."  (Same as a highway).