On 24 Jun 2009, at 15:11, Frankie Roberto wrote:
On Wed, Jun 24, 2009 at 2:45 PM, Richard Mann <richard.mann.westoxf...@googlemail.com
> wrote:
Do relations solve the problem at all? If a track is part of a route
relation, then could a renderer use that as a means of aggregating
the tracks together?
My hunch is that relations probably don't actually help much, unless
you could rely on them being done consistently and accurately.
Hmm...
One idea another OSMer suggested a while back (when the idea of
tagging tracks still sounded ridiculous) is to have some way of
distinguishing between a 'track' and a railway line (or 'corridor'
is perhaps a better word), so that renderers can choose which to
display (and so that the data contains both conceptually different
things).
Not sure how best to implement this. The easiest thing would be to
have the middle track double up as the way which represents the
line, somehow. The hardest thing might be to have ways which mark
both edges of the rail corridor (like how we do riverbanks).
I would suggest that renderers should taker advantage of the fact that
as one zooms out then the different tracks are so close together that
it doesn't really matter in most cases which one it draws and it can
normally choose one at random to draw. As a refinement the relation
could identify the preferred track using a 'role' to say 'draw this
one' for situations where the geometry is very different for the
various ways.
Similarly Junction relations would soak up all the fiddly tracks at
junctions and replace them with one point (and the junction relation
includes an optional 'hint' location to show where it should go).
The selected track is then drawn from the starting junction (using the
location of the junction node rather than the first point on the
track) to the end junction taking via points from the selected way.
This section of track from Finsbury Park through Harringay, Hornsey to
the junction past Aexandra Park might be a good test route to try any
of our proposals. Here is an image showing an overlay for the proposed
simplified rendering where there is only a single stroke drawn to
cover all of the individual tracks.
http://www.flickr.com/photos/peterito/3657058971/
Regards,
Peter
Frankie
--
Frankie Roberto
Experience Designer, Rattle
0114 2706977
http://www.rattlecentral.com
_______________________________________________
Talk-transit mailing list
Talk-transit@openstreetmap.org
http://lists.openstreetmap.org/listinfo/talk-transit
_______________________________________________
Talk-transit mailing list
Talk-transit@openstreetmap.org
http://lists.openstreetmap.org/listinfo/talk-transit
