PS: About 57% of the key “flood_prone” is “flood_prone=yes”. About 42% of the key “flood_prone” is “flood_prone=no”. About 80% of the elements with the flood_prone key are in 15 km × 15 km area in Jakarta. Lukas Sommer
2014-12-28 20:32 GMT+01:00 Lukas Sommer <sommer...@gmail.com>: > Hello. > > In OSM there seems to be concurrent 2 tagging systems for flood > tagging. And each of them seems to be incomplete. > > Just to remember: There are several types of flood. I think the most > common types are: > > – case 1: caused by heavy rainfall: “on flat or low-lying areas when > the ground is saturated and water either cannot run off or cannot run > off quickly enough to stop accumulating” (from Wikipedia article > “flood”). Typically various times during one year – and quite common > in some African countries during the rain season. > > – case 2: caused by overflow of water of a riverbed: not directly > related to rainfall at this spot (rainfall can be hundrids of > kilometers upstream, causing a river overflow hundrids of kilometers > downstream). Typically maybe one per year or maybe each two or three > years… > > In OSM we have flood_prone. The wiki descript fits most with “case 1”: > “ this is mostly applicable to roads that go under water after heavy > rains”; so combining it with highway=* on OSM ways (alternatively on > nodes within a highway) would be the typical use case. We have > currently 204 nodes and 10 582 ways. > > In OSM we have also hazard_type=flood. The wiki description fits > mostly (but not exclusivly) with “case 2”. Tagging areas as > independent OSM elements seems to be the typical use case (no > combining with other objects). We have currently 1 node and 56 ways. > > hazard_type=flood comes from OpenHazardMap – but OpenHazardMap wiki > page hasn’t been updated since one year. OpenHazardMap seems to focus > on landslide (hazard_type=landslide has 3 169 comparing with only 57 > elements for hazard_type=flood). > > Questions: > > – Shouldn’t we deprecate one of these tagging? If so, which one? > > – Shouldn’t we introduce a possiblility to distinguish river > overflowing floods and directly rainfall related floods? > > – Only supplementary tagging of highway=*? Or independent OSM elements > (areas)? Or both? Probably both makes sense. > > Suggestions? > > Lukas Sommer _______________________________________________ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging