[OSM-talk] Beach directions (was: Re: FIXME and other issues)

[Rick Collins]

At 01:28 PM 10/15/2007, OJW wrote:
>On Sunday 14 October 2007 22:22:08 Matthias Julius wrote:
> > I would like riverbanks to work the same way as coastlines. That is,
> > everything to the right of it is water until the opposite riverbank.
>
>
>Talking of which...  has anyone considered marking which side is wet 
>and which
>side is dry on their beach polygons?
>
>Theoretically, the rendering should be some sort of gradient fading into the
>ocean, but that doesn't work so well when the polygon doesn't have
>a 'direction'.


That is easy enough if you consider it to be a standard 
default.  Assuming that the polygon encloses an area and the way has 
a direction, apply the rule that the color will always be to the left 
of the way direction.  So a counter clockwise loop will be filled 
inside and a clockwise loop will be filled outside.  If you draw it 
wrong, just flip the direction of the way forming the polygon.