- Some of the services run through loops. E.g.
A--------B----F---C--------D
| |
+----E---+
they run ABECD in one direction and DCFBECFBA in the other
direction. The
standard route model with unordered data does not allow to
distinguish this
from ABECFBECD forth and DCFBA back.
As I understand it, the ways SHOULD be order. Also, if we go with the
notion of using on-way 'stop points' (ie nodes in the highway
representing where the buses stop, rather than the nodes beside the
highway representing where passengers wait), then those nodes should
be included within the relation too, in order. (This is already done
for some train services).
That said, I don't think one way or node can belong to the same
relation more than once! So you wouldn't be able to map the 'loop'
perfectly yet.
Perhaps an order tag should be added to relations. If you did that then
you could have multiple nodes with different order numbers.
The above example would look something like
<relation id='123'>
<member type='node' ref='D' order='1' />
<member type='node' ref='C' order='2' />
<member type='node' ref='F' order='3' />
<member type='node' ref='B' order='4' />
<member type='node' ref='E' order='5' />
<member type='node' ref='C' order='6' />
<member type='node' ref='F' order='7' />
<member type='node' ref='B' order='8' />
<member type='node' ref='A' order='9' />
</relation>
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