Iswet_flag

• Suggested name of the Locus GUI flag name is Wet conditions

• iswet flag is not about

  • BRouter keywords nor features, as it is a user variable in my custom profiles.
  • Addressing persistent wet conditions. There is OSM tagging for it, like surface=mud, or ford=yes.
  • Relation to any OSM weather specific conditional tagging.
  • Absolute avoidance of ways.

• iswet flag is about

  • Weather related, temporary surface wet conditions.
  • Relative avoidance of ways.
  • Applying the different set of priorities for various combinations of OSM ways and surfaces.
  • Shifted decision point for routing algorithm what way from the alternatives to take.
  • Situations, when a biker feels the overall surface wet conditions crossed his/her personal "wet conditions threshold", depending on riding purpose, surface type and personal perception.

• Iswet applicability

  • The main purpose of iswet in bike context is for trekking bikes on mixed surface network, switching road priorities, if there is "wet enough outside".
  • Paved-road-only bikers may find just a limited use for cobblestone/sett road cases.
  • MTB bikers riding soil/grass only trails may find little use for it, except for hiking note below, or eventually the fallback option if really very wet or if they are already tired.
  • Iswet gets some use for urban area walking on mixed surface OSM network. For hiking on mainly grass/soil trail there is very limited use for iswet flag, like slippery grass or dolomite stones being better than muddy slides.

• Effects of the wet conditions may affect safety, difficulty or just convenience:

  • Slippery of Cobblestone, setts, stones generally and grass
  • Stickiness of sand, dust and fine gravel
  • Soil and dust can get sticky, muddy, slippery, "splashy" and "pondy".

• Iswet implementation

  • Road preferences are in BRouter expressed as costfactor(CF). Iswet increases CF ( by various amount ) for the affected ways and mildly decrease CF of paved ways( but the case for cobblestones/setts ).

• Example

Imagine decision case of 5 km of primary road and alternative unpaved track.(numbers just illustrative )

Track length[km]	Dry conditions decision	Wet conditions decision
1.0	I prefer tracks to cars	Shortcut is good to take
1.5	I prefer tracks to cars	Hmm, but shortcut is still good to take
3.0	I prefer tracks to cars	Hmm, I rather take the primary
5.0	I prefer tracks to cars	...
7.0	I still prefer tracks to cars	...
10.0	Hmm, but I still prefer tracks to cars	...
15.0	Hmm, I rather take the primary	...

---

• Loosely related to Iswet flag are MTB_factor and smallpaved_factor, but they serve different purposes.