A property to denote that an object is covered by something.
covered=* is used to denote that an object represented by a node, way or area is covered.
For highways and railways this differs from tunnel=* in that it is usually open at least on one side or in the case of building passage it has prominent connections to the building. "Covered" is implied for tunnels too.
Also used in some situations where use of layer=* is not meaningfull - when a road passes through a building it makes no sense to assign the road or building different layers.
To be used to:
- covered=building_passage (or arcade, colonade as fitting) when highway or footway is going through a building and has some connection to the building - see Proposed features/building passage. If the way is essentially part of a building level it may be assigned a level=*.
- covered=yes for a highway, railway, pedestrian way or waterway that is (even partially) covered by a building or other structure and does not fit the definition of a tunnel or building passage.
- denote that a power line, water main, water drain, etc., in a narrow trench, has a removable and replaceable covering, allowing for maintenance, and thus potentially allowing it to be traversed without a bridge.
- denote an area such as an underground parking lot, a covered reservoir/cistern or even such things as an aquarium (e.g., Kelly Tarlton's, Auckland, NZ), when the covering is not a man-made structure that would allow layer differentiation.
When should NOT be used:
- on a highway passing under a bridge, where the path of the under-passing highway may be accurately assumed.
- for entities that are buried in the earth or submerged in water. However, underground excavations, such as parking lots and reservoirs are appropriate.
layer=* should be used in cases when the layering is clear and unambiguous. layer=* is probably inapropriate for most cases of covered=building_passage or tunnel=building_passage - except where there is the requirement to differentiate several layers of tunnel=building_passage. Several layers of covered=building_passage may be sometimes more appropriately differentiated with level=*.
When used without layer=* the way should probably have common nodes where the outline of the covering objest is crossed.
An arcade is a succession of arches, each counterthrusting the next, supported by columns or piers or a covered walk enclosed by a line of such arches on one or both sides. Such ways should be tagged with covered=arcade. If the arcade is part of a building, the building and the way share the same node at the entry and exit points. The way is split at the entry and exit nodes and only the part covered by the building is tagged with covered=building_arcade The layer has to be the same as the building. So if the building doesn't have a layer tag, the way doesn't need one either. Use arcade:left=open or arcade:right=open to define which side of the way is open.
When arcade should not be used: It is not meant to be used for indoor mapping. The wall on one side is considered as an outer wall which can have entrances that lead into the building. For indoor mapping indoor=yes can be used. Also it is not meant to be used for simple roof overhangs or blind arcades.
Similar to arcades, but differ architecturally, a colonnade denotes a long sequence of columns joined by their entablature, often free-standing, or part of a building. Such ways should be tagged with covered=colonnade. If part of a building, the building and the way share the same node at the entry and exit points. The way is split at the entry and exit nodes and only the part covered by the building is tagged with covered=colonnade The layer has to be the same as the building. So if the building doesn't have a layer tag, the way doesn't need one either. Use colonnade:left=open or colonnade:right=open to define which side of the way is open.
When colonnade should not be used: It is not meant to be used for indoor mapping. The wall on one side is considered as an outer wall which can have entrances that lead into the building. For indoor mapping indoor=yes can be used. Also it is not meant to be used for simple roof overhangs.
- http://www.fffw.org/Randy/Photos/covered_storm_drain.jpg Covered storm drain - Matsusaka, Japan
- Wikipedia:Snow shed
maxheight=* may also be associated with the covered way or area to indicate clearance.
While layering is the conventional means of showing that one object is covered by another, layering by wiki definition is to denote separate physical levels. There are numerous situations where layering is inappropriate, and can be misleading in the context of the subsystem being mapped. For example, when a building has a way passing through it, and both the way and the building are at ground level, layering the way at -1 or the building at 1, sets inappropriate physical relationships to other surrounding entities. A tag of "covered" on the entity can not only address this issue, but will also make routing more efficient in cases where, for example, a route to avoid the natural elements is desired, or a route to covered parking or to an area for sheltered entry or egress into a vehicle is desired.
In addition, layering of excavated areas such as underground parking garages and reservoirs only shows relative vertical position, and not whether there is a (concrete supported) ground covering over the area.
Rendering would depend on the object being covered, but would, in general, "diminish" the uncovered rendering.
Rendering suggestions include
- parallel dashed lines with no color fill to denote a covered highway. - a lighter or different color to denote a covered pedestrian way. - a dashed line to indicate a covered waterway (blue) or power line (black).
One option would be to render the covering object (in the renderer's drawing sequence) as semitransparent. This would work in most situations, but might not be visually distinct for narrow lines, which might better be rendered as dashed, similar to in tunnels.
This tag potentially deprecates the following tags:
- man_made=reservoir_covered by man_made=reservoir + covered=yes
- misuse of tunnel=yes
- Questionable use of layering