River [Sázava][1] (cz) is mapped twice ([see example][2]). According to the source tag one is an import from some database of waters, the second one has been created manually. What is the best approach to merge these two rivers into one - preserving tags from both? [1]: http://en.wikipedia.org/wiki/S%C3%A1zava_(river) [2]: http://www.openstreetmap.org/edit?lat=49.6288&lon=15.49187&zoom=17http://www.openstreetmap.org/?lat=49.6288&lon=15.49187&zoom=17

River [Sázava][1] (cz) is mapped twice ([see example][2]). According to the source tag one is an import from some database of waters, the second one has been created manually. What is the best approach to merge these two rivers into one - preserving tags from both? [1]: http://en.wikipedia.org/wiki/S%C3%A1zava_(river) [2]: http://www.openstreetmap.org/edit?lat=49.6288&lon=15.49187&zoom=17