[mkgmap-dev] Dead End Check

Thu Aug 30 16:31:13 BST 2012

On 30.08.2012 16:59, Felix Hartmann wrote regarding micromapping:

"Plus access=no
/ access=private and length is up to 50m then delete it"

Felix, I have certainly taken private roads > 50m that led to a pubic 
footpath (what you may describe as unpaved track); and the private road was 
open to pedestrians to use. So I think more care may be needed here - 
although I don't know what the laws are in Germany/Austria regarding private 
roads.

Geoff.

-----Original Message----- 
From: Felix Hartmann
Sent: Thursday, August 30, 2012 3:59 PM
To: Development list for mkgmap
Subject: Re: [mkgmap-dev] Dead End Check

On 30.08.2012 16:48, Marko Mäkelä wrote:
> I think that a more severe problem are routing islands, because they
> really break routing. Some mappers seem to think that a
> highway=pedestrian area is enough and may even delete an overlapping
> highway=* way as garbage.
>
> As far as I know, currently mkgmap does not check for routing islands.
> It might be hard to avoid false positives near tile (or map extract)
> borders. If we ignore that, is it computationally expensive to detect
> routing islands? (Run Tarjan's algorithm and complain if there are
> several strongly connected components in the routing graph, perhaps?)
Oh I also don't think they mess up with routing (at least not much). But
they do visually mess up the map, and take data/space that is not
needed. If this micromapping takes overhand, then at some point, 50% of
all footways are rubbish in Austria. Outside of Germany and Austria such
problems virtually not exist, but it seems here more and more mappers
turn crazy and make Openstreetmap a cadastral map. A simple check for if
lenght is under 10m and it's a dead end, then delete it. Plus access=no
/ access=private and length is up to 50m then delete it, would be enough
to solve 90% of that cases, without any negative impacts (maybe a couple
of wrongly tagged streets disappear, however if the 50m and access=no //
access=private behaviour were in the mkgmap default style, I could well
believe those tagging errors to be corrected quickly, and wrong new ones
corrected quickly too).

Routing Islands are another point. I would love to have mkgmap search
for the nearest routable way at each end of a ferry and
gondolas/chairlifts which is dead ended and connect it via straight line
(using 0x08 in my case, as I set that type to be invisible and as a
"highway link" it would give best routing descriptions).
> Best regards,
>
> Marko
> _______________________________________________
>

-- 
keep on biking and discovering new trails

Felix
openmtbmap.org & www.velomap.org

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