On 2015-07-27 23:39, Lester Caine wrote:
On 27/07/15 20:55, Mike Thompson wrote:
I assumed that when the wiki spoke about "routable" it was referring
to
the water flow rather than boat/ship/barge traffic. In any event, a
routing engine for boats could use the presence of a dam or weir
(combined with the absence of a lock) to deduce that ship navigation
was
not possible.
'This way used should point in the direction of water flow' is only
applicable to non-tidal flows, and reservoirs may well control water
flow in a way that makes a 'water flow map' somewhat difficult to
deduce.
Only if they are entirely artificial. A dam in a river or stream makes
the direction of water very clear: high to low. Only when there is an
artificial reservoir with no natural tributary it is not clear.
The use of 'routable network' is rather ambiguous, but this is little
different to the problem of routing through other land based open areas
where several waterway features link into an area of open water. The
jury is still out on putting in all the paths through the area, but if
there is a navigable route designated through a water body it should be
drawn, but an imaginary link just showing water flow should not be
necessary? Any routing process should be able to deduce the relation,
there is no need to draw it.
Causality. Does a water area need a way indicating the direction of
water? Of is it that when you draw a way through the water area it
should point in the direction of the water flow.
Maarten
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