Am 14.04.2015 um 12:52 schrieb Christoph Hormann: > On Monday 13 April 2015, Torstein Ingebrigtsen Bø wrote: >> Hi, >> >> I'm currently importing topological data of Norway to OSM. From the >> data set we have riverbanks; however, we do not have the deepest >> middle way as required by the wiki [1]. This middle line is therefore >> drawn manually. This is a time consuming (and dull) job. For one >> municipal it takes around 5-10 hours to draw all these lines, in >> Norway we have 428 municipals. Drawing all these middle lines will >> slow down the time to import everything dramatical. I am therefore >> curious of what is the benefits of this line. Is it really necessary >> or is it a "nice to have"? > > It is the other way round - the riverbank polygon is optional and 'nice > to have'. The waterway line is what actually defines a river in OSM, > it also gets the name tag and other attributes. The primary reason for > this is to map the water flow structure. Also it is much easier to > verify and fix structural errors in waterway line mapping than for > water polygons. > > Generating a waterway line when you only have polygons is fairly simple > via straight skeletons (http://en.wikipedia.org/wiki/Straight_skeleton) > If the source data set does not contain continuous line features for > rivers generating those should be part of import preparation. And i > disagree with Janko here - if the source data does not contain certain > information that is required according to OSM mapping conventions you > should not import the data unless you produce the information in some > way (either through manual mapping, computing the missing data or > getting it from other sources). Otherwise the data becomes dead mass > in the OSM database.
+1 Thanks for the wording. Cheers fly _______________________________________________ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
