[Tagging] Feature Proposal - RFC - natural=bare_rock

M∡rtin Koppenhoefer dieterdreist at gmail.com
Sun Jan 30 11:52:32 GMT 2011


2011/1/30 John Smith <deltafoxtrot256 at gmail.com>:
> On 30 January 2011 21:05, M∡rtin Koppenhoefer <dieterdreist at gmail.com> wrote:
>> broken by design...
>> There won't be an "invalid polygon", there would be 2 valid but
>> contradicting polygons.
>
> Which are sorted by smallest first usually so they render on top of
> the larger ones.


This is a method of trying to extract useful data from an undefined
state making assumptions, but it is IMHO not how we should design our
data model. This would also mean that even with complete data for the
whole world, you would need endless processing if you wanted to
estimate the area covered by sand: for every area tagged surface=sand
you would only know it's real extension after subtracting all other
polygons with different surface-values (or with an assumed different
surface).

You also seem to reduce this to a rendering problem.

There can also be cases where a bigger polygon overlaps for a small
part a smaller polygon.

cheers,
Martin



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