Any requirement for polygon ring winding ?

[strk]

Is there any requirement for polygon holes and shell to follow a specific winding ? (clockwise/counterclockwise) ?

Do rings have to end with a ClosePath ?

[sgillies]

@strk We came to the conclusion in https://github.com/mapbox/tilemill/issues/2110 that the right hand rule should be applied to polygons in Tilemill. I propose we do the same for the vector tile spec.

Good question about ClosePath. Requirement of it seems a little redundant since it's already implicit in the geometry type. And Mapnik closes polygons given to it already, right?

[pnorman]

For reference, a multipolygon where the first polygon is an ourter ring of four coordinates and the second is an outer ring of five and an inner of three gives you this result from Mapnik

MoveTo Length 1 [9]
coord x2
LineTo Length 3 [26]
coord x6
ClosePath Length 1 [15]
MoveTo Length 1 [9]
coord x2
LineTo Length 5 [42]
coord x10
ClosePath Length 1 [15]
MoveTo Length 1 [9]
coord x2
LineTo Length 3 [26]
coord x6
ClosePath Length 1 [15]

[flippmoke]

Sorry, didn't mean to close this issue -- this will serve as a great ticket for discussions on the v2 pull request #39

[flippmoke]

As I do not see any objections to the way winding order is described in the new specification going to go ahead and close this ticket.