[Tagging] Difference between lighthouses and beacons
Malcolm Herring
malcolm.herring at btinternet.com
Sun Jan 14 14:11:47 UTC 2018
On 14/01/2018 13:47, Janko Mihelić wrote:
> So a fuzzy rule can be created, you can't have a man_made=lighthouse tag
> and seamark:xxx=yyy tags on the same object. That's instantly an error.
> Seamark tags are used for instruments that help navigation, and
> lighthouses are structures that can house those instruments. But they
> are not the same thing. So a lighthouse can be an area with a seamark
> node at the place where the light is.
>
> Is this generally accepted?
No. Lighthouse objects mapped as building outlines should have any
seamark tags on the way as opposed to a separate node. This arrangement
is easier to maintain. As most lighthouses have their lamp centrally
placed in the building, the light position can inferred by calculating
the centroid of the area.
The bigger problem is defining exactly what is a lighthouse & what is
just a beacon. I agree that a lighthouse should be a building with
living quarters. Often beacon towers, whether masonry or metal towers
that support a navigation light are tagged as lighthouses - which is
incorrect. Part of this is 'tagging for the renderer', so that a symbol
is placed on the main map, but often it is the lack of a clear
definition of a lighthouse.
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