[Tagging] simple_brunnel : one node bridge like xing highway over waterway

Martin Koppenhoefer dieterdreist at gmail.com
Wed Apr 2 16:33:15 UTC 2014


2014-04-02 18:16 GMT+02:00 Mike Thompson <miketho16 at gmail.com>:

> > It is also a significant loss of detail because you reduce the length of
> the bridge to 0
> Maps are abstractions. They don't represent reality precisely.
>



We aim at precision/accuracy (IMHO, at least I do), you can always create
more abstracted maps from precise geodata, while the other way round it is
not possible.



>   In most cases we already reduce the width of roads to 0 as they are not
> represented by areas.
>


no, their geometric representation is a line, but their width is (or can
be) added with a tag like width and lanes, of which the latter defaults to
2 (for non-links) if not added explicitly.




>  The question should be whether the value of the data is significantly
> degraded if some very short bridges are represented as nodes.
>


OK. Can you explain how long a "very short bridge" should be? What is the
benefit of this kind of mapping style?
In this context I'd like to point out that GPS precision is not the limit,
you do not have to take 2 waypoints at the beginning and end of the bridge
and the result will become your bridge, automatically, usually you will
interpret these waypoints and will estimate the bridge length and represent
it according to your estimate, so I do not think a 3 meters long bridge
will result in a 45 meters long zigzag in your mapping, just because you
had bad GPS reception under the tree canopy and made a break on the bridge
;-)


cheers,
Martin
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