The stream direction is very handy if you are doing network analysis, just like one way streets are important to routing vehicles through a street network. As with any data, its always best to code objects correctly in the first instance to save time later. In some cases it is pretty difficult to determine which way streams flow as pointed out by Liz and in these instances it may be worth putting a "fixme=direction" tag onto the stream.
Having said that I doubt anyone would be using OSM data for streamflow analysis because topographic features are not the main focus of OSM. Craig On Wed, Jul 28, 2010 at 1:39 PM, John Henderson <snow...@gmx.com> wrote: > I note the wiki says that "Direction of the way should be downstream." > > Most streams I look at on OSM have been drawn uphill, and I've been > reversing the direction of ones I notice as wrong. ?Indeed, I find it more > natural to draw streams that way myself, and then reverse them. Yep, the only way to draw them facing downstream is to start at the source, and that's pretty hard. I usually find them where they join another river, so am probably contributing to the backward mapping. Anyone know of any applications that use the direction of streams? Steve
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