[Tagging] Planning route in the shade during hikes either in urban areas or forests

[bkil]

Consider the interpretation of shade=* as being a cuisine of lit=*. We
don't split a sidewalk around every street lamp to indicate high
brightness and again split it around each and every tree and bush that
could cast a shadow on the sidewalk. Rather, we just indicate whether
certain longer, approximate sections of road have roadside street
lamps installed or not. As not many map or photograph at night, we
don't even know whether the lights are working. I know some badly
maintained streets where many of the street lights are surrounded by
foliage.

People just add lit=yes to highways at first, but as aerial
photography becomes available, they may opt to map each and every
street lamp. Unfortunately, to this day, micromapping or visualizing
light sources still can't be done properly: consider statues, bridges
or places of worship being lit by spot reflectors, advertising columns
and signs may produce light in given directions, certain 24/7 POI may
emit light in various ways that can all give usable light to highways
(aerial photos taken at night might even show some of these clearly).

I use the following phrases to describe this liberal application of lit=*:
- mapping as a mature adult
- using common sense
- understanding the intention
- trying to avoid a maintenance burden
- serving a well defined purpose
- minimal possible effort
- supporting progressive improvement
- very easy to integrate with any data user (router or map)
- can quickly finish completely mapping this in any given village

Coming from this same direction, given the street level imagery of a
street (even just 1 photo of each stretch of road between corners), in
a substantial number of localities, it would be feasible to rank the
given stretch based on how shady it should be during the day compared
to all other stretches nearby.
- If a sidewalk is covered by a mature tree row, it should be shady,
- If no foliage covers a sidewalk but there are high rising structure
just besides the two sides of the road or foliage is nearby the
sidewalk, it would be shady in limited times of day varying by place
- Otherwise it's not particularly shady.

See my original user story (actually a FAQ) in $SUBJECT. As a
pedestrian, one can have this desire and OSM folks had been appointed
to give an answer to this problem (as Google Maps can never solve a
problem like this). Answers could be ranked by cost vs. benefit. We
have shared a minimal valuable product approximation in spirit of
lit=* above. You may argue that it is not precise, but surely this is
what a coarse approximation means.

You may argue that only a 3D solution should be endorsed, but do note
that even if somebody implemented a router for that, who is going to
map and _maintain_ all this data around the world? You may do it for
your particular neighborhood, but as its cost is prohibitive (like
100x-1000x as shade=*), it will be the norm that this information will
be missing from the map for the majority. You may possess
- imported government data about buildings (though not always the
height, roof shape and other minor quirks of its geometry),
- imported data about trees (along with taxon, age and height),
- width of the sidewalk/footway,
- data for fences (though that's not very common, especially height and type).

But how common is it that one would have all required data? Around
here, none one of these are available and thus most of the map is
blank in this aspect.

On Sun, Jul 4, 2021 at 11:10 AM Frederik Ramm <frederik at remote.org> wrote:
>
> Hi,
>
> mapping shade is not a good idea, especially since you're building a
> false dichotomy with your
>
> > As an alternative, it would be possible to map each and every tree and
> > hedge, along with its taxon, height and crown_diameter, each fence
> > with fence_type and each building and other structure in 3D, each
> > sidewalk with exact material and geometry
>
> because precisely mapping shade=* would be almost the same effort, as
> you'd have to split up a way every couple of metres to specify the shade
> conditions which have now changed due to some other built structure -
> not to mention the time-of-day effect you already mentioned.
>
> Mapping buildings and trees with their height can also give you a
> reasonable approximation of how much shade there will be in a certain
> area at a certain time of day (and year).
>
> See http://pintsinthesun.co.uk/ for a proof of concept ;)
>
> Bye
> Frederik
>
> --
> Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00'09" E008°23'33"
>
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