[Talk-transit] Multiple tracks

Joseph Booker joe at neoturbine.net
Mon Jun 22 01:22:58 BST 2009


On Sat, 20 Jun 2009 12:18:43 +0100
Richard Mann <richard.mann.westoxford at googlemail.com> wrote:

> While I like the idea of marking individual railway tracks as
> separate ways, I foresee a problem for the renderers if we don't tell
> them how many tracks are adjacent. If a renderer makes a distinction
> between tracks=1 and tracks=2, and we've marked two separate adjacent
> ways with tracks=1, then we'll just end up with two single tracks on
> top of each other at medium zooms.
> 
> My thought is that we either make it tracks=1of2 or have a separate
> track_grouping=1of2. Anyone else have a better idea?
> 
> I've put a comment to this effect on the multiple_tracks proposal,
> but this list doesn't see much traffic, so I thought I'd raise it
> here.
> 
> Richard

What if the adjacent tracks are physically 20m away, or 30m or 40m
away, but they are still part of the same rapid transit or freight
lines? Does tracks=1of2 imply that they must be close enough to overlap
at a given zoom level?

Honestly, I think the real problem with your proposal is you talk of
zoom levels like they are a definite thing. There are more renders then
just mapnik, and exactly what corresponds to 'medium' zoom seems like
you're putting renderer details into the data.

-- 
Joseph Booker
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