[Tagging] Feature Proposal - RFC - key:spacing=*

[Christoph Hormann]

On Saturday 05 May 2018, Peter Elderson wrote:
> [...]
>
> The key is proposed as part of a rendering proposal for
> *natural=tree_row*, [...]
>
> However, the proposed usage is explicitly non-exact: [...]

As a general rule a good tag or tagging proposal should be mapper 
oriented, it should be designed to allow mappers to document verifiable 
aspects of the observable geography in an efficient, precise and 
non-ambiguous way.

Why don't we tag spacing=* on a power=line instead of tagging every pole 
with power=pole?  Because if we have the information and the time as a 
mapper to verifiably determine this we can normally also go ahead and 
map the poles anyway which makes the data much more meaningful and 
valuable in general.  And because actually measuring the spacing 
between the poles, in particular if it varies, is practically harder 
than just mapping the positions of the poles.

If i try to ignore the rendering related aspects of your proposal it 
boils down to being deliberately non-exact.  Why would a mapper want to 
do that?  If i want to map a tree row in a quick and dirty way i draw a 
way and tag it natural=tree_row.  If i want to map it in more detail i 
map and tag the individual trees.  I don't see tagging spacing=* as an 
intermediate solution here.

If as a style developer you want to render tree rows styled depending on 
the tree density the way to go would IMO be to encourage mappers to map 
individual trees (which current documentation of natural=tree_row 
considers valid when done in addition) and determine the spacing from 
these.

-- 
Christoph Hormann
http://www.imagico.de/