[OSM-talk] How to fix wonky coastline?

[David Earl]

> What?? Honestly, are you serious? All we need to do is to use
> *POLYGONS* ,
> full stop. What is the problem?

That the polygons are huge (absolutely massive - the whole of Asia for
example) in relation to a tile. If you have a 256 pixel tile to consider,
why would you have to obtain the whole African coastline in order to render
that small tile (if indeed you are even able to download that much data in
tiles at home for example).

OR alternatively the sea (or land) has to be broken up into very large
numbers of manageable size polygons, most of which don't contain a coastline
(e.g. squares; else how do you know that your landlocked town shouldn't have
a sea-colour background?).

It is just so much simpler for the renderer to make decisions at the same
kind of scale as what it is trying to render.

Furthermore, the coast is already represented as lots of unconnected ways,
so it is easier to get from where we are now to where we want to be if we
stick with that representation.

> This [point in polygon] will never work reliably.

It is heuristic I agree, but I bet it would deal with 99.99% of cases and it
will be very obvious indeed when it goes wrong to manually fixup the few
remaining cases.

I think you are being altogether too dogmatic. I am trying to make some
suggestions which could improve efficiency, and you are dismissing them out
of hand.

David