[Tagging] Feature Proposal - RFC canal=qanat

Christoph Hormann osm at imagico.de
Sat Sep 1 15:04:14 UTC 2018

On Saturday 01 September 2018, Joseph Guillaume wrote:
> I'm planning to map some qanats, underground channels for conveying
> groundwater that have vertical excavation shafts visible from the
> surface/aerial imagery (see proposal for example).
> [...]

What you need to consider here is if you want to make this tagging 
fairly specific to what is locally called "qanat" or if you want it to 
be used for a broad range of objects also in other parts of the world.  
In the latter case having a clear abstract definition what the tag is 
meant to describe physically that is not just a description of what a 
qanat is would be essential.  Both variants have their advantages and 

Apart from that it is important to remember that waterway=canal is only 
for free surface flow - for pressurized tunneled waterflow 
waterway=canal is not suited.  If you want to use the same tagging for 
both you should choose a different primary tag.  Qanats built in loose 
ground are exclusively free surface flow but there might be mixed 
constructions in some cases.

In any case it is very good to see distinct tagging being developed for 
this kind of feature and not just generic underground waterway tagging 
being used.

Christoph Hormann

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