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

Peter Elderson pelderson at gmail.com
Sat May 5 10:12:34 UTC 2018


 Feature Proposal - RFC - key:spacing=*

https://wiki.openstreetmap.org/wiki/Proposed_features/Key:spacing%3D*

According to Proposal Process
<https://wiki.openstreetmap.org/wiki/Proposal_process#Proposed>:

   - Please discuss each proposed feature on its own discussion page.


Proposed feauture is a new key:*spacing=** to indicate estimated average
spacing (or it's counterpart: density), of objects along a way or on an
area.

The key is proposed as part of a rendering proposal for *natural=tree_row*,
but it's easy to see how it can be applied to any case where objects are
more or less grouped or arranged together with a kind of regularity. In
that respect spacing=* is a general purpose dimension tag like height,
width, length and ele.

However, the proposed usage is explicitly non-exact: think of the spacing
of trees in a tree_row or in a forest, or a barrier consisting of lengths
of fence between poles. These objects are often described verbally as "very
dense", "a tree every 10 feet" or "widely spaced, about 50 meters apart".

So the goal is to give an indication of the spatial distribution along the
way or over the area, rather than an exact measurement of distances between
separate actual objects. If exact positions are required for all or some of
the trees in a row, these trees should be individually mapped and tagged as
natural=tree. (The individual nodes may be attached to the tree_row way,
which provides an easy method for aligning tree nodes within a row, but you
need to tag them separately.)

That way you don't need to worry about the dimension or shape of single
objects, or that in fact some are 9 m apart and others are 11 m apart.
Measurement is simple: take a sample length of the way divided by the
number of sections (= #objects minus one). For people who think exact:
picture a grid where every point is N m apart from it's neighbours, then
objects are placed on or near the grid points.
Tagging[bewerken
<https://wiki.openstreetmap.org/w/index.php?title=Proposed_features/Key:spacing%3D*&veaction=edit&section=4>
 | brontekst bewerken
<https://wiki.openstreetmap.org/w/index.php?title=Proposed_features/Key:spacing%3D*&action=edit&section=4>
]

*spacing=N* where N is average space between points representing objects
(e.g. average heart-to-heart distance between trees)

units are in m unless otherwise specified (N u).

Use with natural=tree_row, natural=wood, landuse=forest, landuse=orchard,
natural=scrub, barrier=hedge, or any other way or surface with more or less
regularly spaced objects.

Note that the key gives spacing for the whole way or area. It is not an
attribute of the objects themselves and does not imply exact placement of
the objects.
Applies to[bewerken
<https://wiki.openstreetmap.org/w/index.php?title=Proposed_features/Key:spacing%3D*&veaction=edit&section=5>
 | brontekst bewerken
<https://wiki.openstreetmap.org/w/index.php?title=Proposed_features/Key:spacing%3D*&action=edit&section=5>
]

   - linear ways representing a loosely or densely spaced row of objects,
   exemplified by a tree_row. Other examples: a row of bollards, a row of
   stepping stones to cross a waterway, a row of street lights.


   - areas representing a surface loosely or densely covered with objects,
   exemplified by a forest or an orchard.


-- 
Vr gr Peter Elderson
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