> Admin boundaries do not specify any required direction. So there is no > incompatibility with river centerlines used as admin boundaries. In the same > way, there is also no incompatibility with one-way road centerlines being > used as admin boundaries too. Thanks Eugene for this clarification.
> It started me thinking though. If you were able to get the elevation data for > the > start point and end point of a waterway, you could probably work out the > direction > of flow from that, and apply it automagically. What we do in JOSM is to add the OpenCycleMap layer as another background layer to determine the highest point and use the Bing imagery to trace the waterways. > tidal estuary For tidal estuaries like those in Bulacan, Pampanga and north Metro Manila, I agree this is difficult. But in most cases, we assume the water drains towards the sea as Rem suggested. -- cheers, maning ------------------------------------------------------ "Freedom is still the most radical idea of all" -N.Branden wiki: http://esambale.wikispaces.com/ blog: http://epsg4253.wordpress.com/ ------------------------------------------------------ _______________________________________________ talk-ph mailing list talk-ph@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk-ph
