|subkey: "structure", Key:building:structure, Key:roof:structure|
|Status:||Proposals with undefined or invalid status (inactive)|
|Tagging:||building, roof, building:structure, roof:structure=*|
|Applies to:||, ,|
|Definition:||Structure is defined as “the arrangement of and relations between the parts or elements of something complex”|
This proposal adds additional values to the "building" key and the "roof" key, introduces the "building:structure" key and the "roof:structure" key with possibility of application to other relative keys such as "bridge:structure" (in proposal stage), "highway:structure", "tunnel:structure" and other forms of physical man made features and infrastructure to offer a more extended description of those elements in a more technical description.
The key building:structure is describing the building technology or main materials used in the making of a certain building.
The key roof:structure is describing the two main parts of a roof. Its supporting structure and its outer skin, or uppermost weatherproof layer.
During our project of NGT Zanzibar, we came across with the need to describe in more detail which building technique our buildings were made of in order to stand out certain techniques that are slowly going into extinction and are of historic value and importance. The subkey "structure" could offer to mappers provide more specific and in-depth information about their mapped features and their load-bearing types. Readers could get more technical information and statistics about available or most popular building techniques in an area.
Building:structure key list of NGT values
|building:structure||wattle_and_daub|| Wattle and daub is a composite building material used for making walls, in which a woven lattice of wooden strips called wattle is daubed with a sticky material usually made of some combination of wet soil, clay, sand, animal dung and straw.
|building:structure||concrete_frame_and_cement_blocks|| Building technique in which concrete counteracted with steel reinforcing bars is forming the building’s structural system, while the filling of walls is made of cement blocks.
|building:structure||cement_blocks|| Masonry technique of making mainly one floor buildings with cement blocks and a binding material. Sometimes reinforced with simple concrete rings.
|building:structure||coralstone_and_lime|| Masonry technique of making stone structures from a type of limestone called coralstone, a binding lime mortar and lime plaster.
|building:structure||makeshift|| "Acting as an interim and temporary measure” 
A structure that was made with whatever material was around to meet a certain immediate need.
Roof:structure key list of NGT values
|roof:structure||concrete|| Concrete slab.
|roof:structure||timber_frame_and_metal_sheets|| Supporting frame is structured with a framework of a timber roof truss, covered with corrugated iron sheets.
|roof:structure||timber_frame_and_roof_tiles|| Supporting frame is structured with a framework of a timber roof truss, covered with roof tiles.
|roof:structure||bushpole_frame_and_makuti|| Supporting frame structured with bush poles and roofing made of makuti thatching.
In general, these proposed values should be mapped in the same way as "building=yes", "roof=yes".
Please add comments on the proposal here.
Please comment on the discussion page.