[josm-dev] Clockwise coastline, anti-clockwise water

[Roy Rankin]

Dirk Stöcker wrote:
> On Mon, 7 Jul 2008, Roy Rankin wrote:
> 

>> I just looked at the patch again, and although I corrected the if
>> statements, the error messages are wrong for coastline and water. I
>> think that errortype should be "Anti-clockwise coastline" and
>> "Anti-clockwise water".
> 
> Actually that is not, what the code does.
> 
> It checks for
> 
> anti-clockwise coastline
> anti-clockwise land
> clockwise water.
> 
> The problem is probably in semantics:

Opps,

I missed the fact that when talking on the direction of coastlines, 
anti-clockwise is relative to the land and thus the test is incorrect 
concerning coastlines.


> 
> http://wiki.openstreetmap.org/index.php/Tag:natural=coastline
> States as anti-clockwise, but regarding the land surrounded by water
> 
> http://wiki.openstreetmap.org/index.php/Tag:natural=water
> States clockwise, but regarding the water itself and not the land.
> 
> Thus it seems the code must be fixed to handle coastline equal to 
> water. And I will change the text, so it uses right and left 
> instead of clockwise.
> 
> Now the remaining questions is natural=land. When should land be in this 
> case?
> natural=water --> land left
> natural=coastline --> land left
> natural=land --> land left?

For natural=[water, land, coastline] the rule is always "land on left 
water of right" when facing in the direction of the way. The land rule 
is in http://wiki.openstreetmap.org/index.php/Map_Features#Natural. 
Which would make the above correct.

How does the following sound for errortype
water - land not on left
land - land not on left
coastline - land not on left

Regards,
Roy Rankin