Qanat

qanat is a very important structure in some countries like Iran. At the time being there is no way to show them on map. We need some nodes to show wells and a line to connect them to each other. These wells have characteristics like deep and number or name.
https://en.wikipedia.org/wiki/Qanat

If I understand correctly this is underground facility? Then it should not be rendered on standard map in my opinion.

“what should be rendered” is irrelevant to “what should be mapped”, surely? OSM’s “standard” map shows only a very small amount of what people actually add to OSM, and other specialist maps fill in the gaps. Somewhere there’s a map that shows everything that people add to OSM.

As an example of “not rendered but mapped”, take for example http://www.openstreetmap.org/relation/2734272 . It’s mostly underground, but once you know what to look for you can see indications of its presence everywhere it goes.

In the case of Qanats, I’d suggest looking to see where other similar things around the world have been mapped - places where water is moved around or the natural movement of water is exploited (adits, used to drain water from mines, are one example that springs to mind).

OSM’s mailing lists (such as https://lists.openstreetmap.org/listinfo/tagging ) are probably the place to post if you want more replies. Some of the country and language forums are very popular and widely used, but for tagging discussion in English you’re probably better off asking elsewhere.

There are reasons for mapping and rendering Qantas:

Qantas are ancient structures. Some of them are made more than 2000 years ago. UNESCO has a special notice to them. Some of them are registered by UNESCO as Cultural Heritages

Some of Qantas have great attractions for tourists and also scientists.

Qantas can be very dangerous because hundreds deep ancient well on the ground can swallow people who don’t know any about the land they are driving or walking. Unfortunately there is no sign to alert people and abandoned ones are more dangers than others.
Besides the kilometers of underground tunnels that are washed by water during 2000 years are susceptible to be collapsed. Therefore it is necessary for you to know the locations of these tunnels.

There is draft for tagging qanats (and also some remarks about rendering):

https://wiki.openstreetmap.org/wiki/Proposed_features/Qanat

There’s only something close to the qanat shafts, but it might be not proper way of tagging:

https://wiki.openstreetmap.org/wiki/Tag:man_made%3Dmineshaft

Once some tagging is defined and used, one can propose rendering on standard map:

https://github.com/gravitystorm/openstreetmap-carto/issues

or try with another style (or create your own) - HOT style might be the best candidate, I guess:

https://github.com/hotosm/HDM-CartoCSS/issues

Currently there’s only minor usage of these new proposed tags:

https://taginfo.openstreetmap.org/tags/man_made=qanat
https://taginfo.openstreetmap.org/tags/qanat=shaft

A good way for the old Qantas would be historic=aqueduct and aqueduct=qanta.

Please refer:

http://gk.historic.place/historische_objekte/translate/en/index-en.html?zoom=16&lat=41.87153&lon=12.5416&select=w113758266&pid=HaHbHcSaHe

Greetings from Lutz