[Tagging] Tagging an area for seasonal snowfall?

Lauri Kytömaa lkytomaa at gmail.com
Wed Feb 17 19:10:48 UTC 2016

Martin Koppenhoefer wrote:
>> http://wiki.openstreetmap.org/wiki/Key:seasonal:snowfall:regaintime
> this looks like a completely useless tag to me, or at least misleading and
> prone to guesswork and phantasy mapping. If I understand it right, the tag
> tries to say something about the usage frequency of footways in the winter,
> but uses quite subjective criteria and has a lot of undeterminable variables
> in it (e.g. how much snow in what time, what are the temperatures (because
> lower temperatures will lead generally to less people walking, just as will
> precipitation, while sunny weather will encourage more people to go outside,
> also walking). From my own experience, ways are more "easily walkable in
> dress shoes" if you're the first to use them (but this might depend on the
> amount of snow), while ways that get used a lot have to be treated or will
> become slippery ice ways soon. etc. etc.


I believe I need to say something about this, because most of those
have been entered by me. I did consider, and discuss this with other
local mappers long ago when we tried to consider what can we say
about ways that aren't snowplowed, but are evidently valuable routes
because they... are used anyway, whereas the next one isn't.

If there's so little snow that you can easily walk in dress shoes as the
first pedestrian after the snowfall, the way never had to be "regained",
there's just a shallow white cover that doesn't impede on your travel.

Temperature has nothing to do with it, in the sense that if it gets colder,
even if there's generally fewer pedestrians, the preference between
snowplowed and various possibly shorter but practically blocked with
snow ways stays the same - to a large extent anyway - and it's not the
same as the year-round usage frequency. Once days have passed
since the last snowfall, most - but not all - ways likely have turned to a
solid surface from walking, and are again as good a choice as the
next one.

The point is that the usage frequency changes from the non-snow
conditions in a predictable and mostly repeatable manner when there's
enough new snow that unless the way is snowplowed, people rather
take a detour - except if it's a valuable shortcut (valuable for some
reason, which we don't need to care about), it's regained first. As
another example, an unmade forest trail in the city park might not be
traversed on foot the whole winter, or it might be the most popular path
taken by dog walkers throughout the winter and practically always
"open", despite not seeing any snowploughs. It's even easier to verify
than the amount of route users, because you only need a few samples
after separate days of snowfall to see which ways have already been
regained on every occasion, and which seem to be forgotten until the
spring comes (and few values between those ends of the axis).


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