[Talk-us] Freeway exit tagging

Greg Morgan dr.kludge.gm at gmail.com
Fri Aug 26 05:59:47 UTC 2016

> mapping the road markings seems extremely strange - what if they are very
> faded, when do we map them ? is there a threshold of % of the paint left ?
> what is there are no road markings but there are signs ?

I encouraged MapBox to add some of their workflow information to the
wiki page.[1] The MapBox team will be the first to tell you that they
may not get things right.  However, I'd rather follow their lead right
now because they are making an effort to improve navigation.

I don't see how the questions help with the discussion.  I believe
that you are asking questions for something that does not exist.
1.The sun beats down on asphalt.  That's why I mark a road as
surface=asphalt and not surface=paved.  Asphalt handles so much
differently than concrete.  Up north water seeps into the cracks and
freezes.  This process generates frost heaves, where potholes form in
the road.  Down here in the land of the sun, the cracks are filled
with tar until the point of no return sets in just like frost
heaves.[2] The street feels like you are driving on cobble stones.
2.A pavement profiler comes in and removes the asphalt near the
sidewalk so there is less of a bump.  At this point, the picture shows
that the new asphalt was laid down.  Note the appropriate safety
3.Days later there's a new glassy smooth road with new lane lines.[4]
I don't even bother adding construction tags when a road is being
resurfaced.  It is over and done too quickly to bother with.

> do we remove those tags during the winter in some regions ?
The tags stay the same in both good and bad conditions.  You have
drifted into hyperbole at this point. In the snow filled north and the
sunny south, these are still usable roads.  It would be useful to know
that there are three lanes on a snow packed street when only one is
drive-able.  The lane count and turn lanes are also useful knowledge
when the freeway is flooded and you are looking for an alternate
because the street ahead has only two lanes functional piled high with
freeway traffic.[5][6]

I would rather attempt to add the information for routing rather than
have no data.  NINO is far worse than the alleged GIGO.  The community
needs to let mappers attempt to understand the problem and improve
upon the knowledge or tagging.  My eyes glazed over when I looked at
the wiki page. I found sanity to the MapBox workflow.[1]

[1] https://github.com/mapbox/mapping/wiki/Mapping-guide-for-turn-lanes-from-imagery
[2] http://mapillary.com/map/im/AwRbJa0dDr_RSnnjteTTFA
[3] http://mapillary.com/map/im/i40PBdYRIMs7vHttf_SiZg
[4] http://mapillary.com/map/im/ZUvJ4et2qVGLC8JJDl43CQ
[5] http://mapillary.com/map/im/AbmqIXz9Wi0EQMoLLiSLyg
[6] http://mapillary.com/map/im/QHY4gXilNHH2yyp9PEInlA

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