Hi! Am 09.04.2013 um 17:22 schrieb François Lacombe <francois.laco...@telecom-bretagne.eu>:
> In my mind, define a role in a relation is mandatory but you say it's > definitely not right. Roles can make sense. For example ways in a route relation may have the role forward or backward, if this specific way is only used in one direction. This is a property of the route and not of the way, therefore it is tagged as role in the relation. A generator is different. It simply is a generator and its role within the plant is to be a generator. So there is no need to explicitly specify it. Furthermore think of the consumers. Example: the process one feature of the plant. If the plant is described by a relation the consumers have two sources about the type of that feature: the tags on the feature and the relation. As the relation is not always present they will trust the tags on the feature and ignore the role in the relation. > I agree to say generator / substation and other roles are not relevant and > maybe redundant but they formalize association between features and power > plant, which features' tags (or plants' tags) won't do ever since they're > attached to objects, not to the link between objects. Which association would they formalise? If a generator is part of a plant its function (aka role) is to work as generator. The association is created by adding the generator to the plant. > To make proposal lighter I would consent to remove generator, substation > roles and most of the specific roles from non-enclosed power plants relations > (perimeter has already left the proposal as you maybe noticed). I'm just curious about the perimeter: what would we do if a plant has multiple perimeters? How would we map them? > But that will allow mappers to use any values they want to use, not convince > them into letting the "role" field blank. Does it matter? Besides some special roles defined by the proposal, what would a consumer do with an unknown role? Best regards, Martin _______________________________________________ Tagging mailing list Tagging@openstreetmap.org http://lists.openstreetmap.org/listinfo/tagging
