[Tagging] Advice & clarification of the railway tracks=* tag required.

David ``Smith'' vidthekid at gmail.com
Tue Aug 14 13:44:07 BST 2012


On Aug 14, 2012 7:48 AM, "Pieren" <pieren3 at gmail.com> wrote:
>
> On Tue, Aug 14, 2012 at 1:03 PM, David ``Smith'' <vidthekid at gmail.com>
wrote:
>
> > A little bit of redundancy is fine if it makes the data significantly
easier
> > to use, IMO.
>
> Excepted that ITO map is interpreting the tag as it is documented. If
> you zoom at the maximum [1], you will see that the renderer is drawing
> 4 parallel lines in colour "red" which means 4 times "4,5 or 6
> tracks".  It is not redundancy, it's simply wrong.
> How can you distinguish when "tracks" is used as it is documented or
> when it's used as RM interprets it ?
>
> Pieren

That's why I suggest using tracks=* as the wiki describes, and putting the
total number of tracks in a new tag like total_tracks=*.  Then people can
use ITO on the new tag, or otherwise render maps colored by total number of
tracks, without having to implement extra analysis of the data.  Presumably
such maps are presented at such a scale as to make it impossible to see how
many separate ways are drawn along a given railway line.

My reference to redundancy was about having the total number of tracks
explicitly tagged, in _addition_ to the summation of _correct_ tracks=*
tags on however many ways are drawn.

For example, if one way represents four tracks, it should be tagged
tracks=4 + total_tracks=4, meaning "this way represents all 4 of 4 tracks
present in the right-of-way".  If those four tracks are drawn as individual
ways, each way should be tagged tracks=1 + total_tracks=4, meaning "this
way represents just 1 of 4 tracks present in the right-of-way".

Having a separate tag for this summary information should solve the
original "problem" which motivated misusing tracks=* in the first place,
without breaking things.  The only downside is a bit of redundancy, for
which I've already provided a justification.
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