[OSM-talk] The Return of the Highway tags and other junk

[Dirk-Lüder Kreie]

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Ben Robbins schrieb:

> This switching of value to key is illogical I think.  Using this method it 
> may as well be like that for everything.  Motoway=yes, residential=yes 
> JOSM=yes.

I have several issues with the current tagging system, nevertheless I
use it to the existing standard, because at the moment I cannot come up
with something better.

>> gates & cattle grids are applied no nodes and not ways, so don't seem to 
>> come into the matter.
> 
> I don't wish to be repetative, but gates and cattlegrids take up an area, so 
> nodes is incorrect.

Nodes are mathematical points, segments are mathematical lines, so
technically these are all incorrect. However there is some default space
usage assumed, depending on the attributes of the node/segment/way.
So if you tag a node "cattle grid" it should be clear that the cattle
grid is a non-dimensional thing but something that will span the entire
width of the road at that point and occupy some length of the road as
well. The Method of data gathering of OSM is not accurate enough to
warrant a mapped area for something as small as a cattle grid. Or a gate
for that matter.
Even a house may only be one node, centered at the house location. Od
take a building of public interest if you want to find it, you only need
the position (one node) and maybe (if ambiguous) the road(s) from which
you can (not) access it which can be sufficiently represented by
segments/ways.

Remember that a map is always a simplified model of the world, you have
to leave out insignificant information for example the exact dimensions
of a cattle grid or gate, that only matters if it limits traffic, by
means of maximum weight, width and/or height.


Dirk-Lüder "Deelkar" Kreie
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