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<body class='hmmessage'><div dir='ltr'>Hi Felix,<br><br>the via_ways branch tries to implement the information that is stored in restriction relations:<br>http://wiki.openstreetmap.org/wiki/Relation:restriction<br><br>The Garmin format also has a so called "route restriction". It allows to say <br>something like "if you come from node n1 travaling on arc a1 to point n2, you are<br>not allowed to travel on to point n3 via arc a2.<br>The so called 4 node restriction is similar : if you come from n1 on a1 via n2 and n3 on arc a2 you<br>are not allowed to continue to n4 on arc a3. <br><br>So, it has nothing to do with invisible ways.<br><br>What you are asking for is an algo similar to that for the --adjust-turn-headings option.<br>I don't think that we really need invisible ways for that, it should be enough to <br>manipulate the angle between the roads which is stored in the img file.<br>My understanding of the Garmin algo is that it doesn't like sharp angles,<br>so I am pretty sure that the angle has an effect on routing. <br>I'll do a few experiments with that.<br><br>Gerd<br><br><div><hr id="stopSpelling">Date: Thu, 3 Apr 2014 10:42:57 +0200<br>From: extremecarver@gmail.com<br>To: mkgmap-dev@lists.mkgmap.org.uk<br>Subject: Re: [mkgmap-dev] r3165 in via_ways branch<br><br>
Hi Gerd,<br>
I haven't really understood what the via ways branch is doing...<br>
<br>
Could you explain it again?<br>
Is it only about restrictions?<br>
<br>
<br>
What could really improve the maps for me would be short invisible
short via ways on all intersections in order to reduce the turn
angle...<br>
So instead of <br>
<br>
|<br>
|<br>
-----|------<br>
|<br>
|<br>
<br>
make every intersection (on those places where the angle is over
60°) look like<br>
|<br>
/ | \<br>
-----|------<br>
\ | /<br>
|<br>
<br>
<br>
Basically building short invisible via ways (if invisible routing
lines are not what this is about, then just give a style/command
option possiblity to define the type and then set it invisible in
the typfile) for routing (basically the same as highway junctions
are in reality, just smaller but serving the purpose of having no
sharp turn angle).<br>
I'm pretty sure this would improve routing a lot for my maps, but
this is only an assumption as I cannot build large maps to try it
out... (the via ways should'nt be straight as in the above example
but of course round to minimize the angle. Length of 10m is long
enough - so make em consist of 3-4 points).<br>
<br>
<br>
<div class="ecxmoz-cite-prefix">On 03.04.2014 09:28, Gerd Petermann
wrote:<br>
</div>
<blockquote cite="mid:DUB112-W1262F15273DD8322C5BD7069E6C0@phx.gbl">
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<div dir="ltr">Hi all,<br>
<br>
I think r3165 is ready for a deeper test.<br>
Changes compared to trunk:<br>
- handling of RouteRestrictions was mostly rewritten to make
sure that mkgmap doesn't<br>
write wrong restrictions to the img file (this was possible
when different roads connected the same points<br>
with direct arcs)<br>
- added support for restrictions with one via way (see below)
<br>
- added support for tag type=restriction:* , e.g.
type=restriction:motorcar <br>
- added support for tag restrection:*=<turn> , e.g.
restriction:motorcar=only_left_turn<br>
- added support for no_entry and no_exit restrictions<br>
- improved log messages for invalid or possibly obsolete
restriction relations<br>
<br>
Reg. via ways: <br>
According to NodCheck in the display tool the data written by
mkgmap r3165 is correct,<br>
but I found no effect on routing :-(<br>
Up to now mkgmap adds a 4 node restriction to both end points
of the via way.<br>
Maybe there is a bit in a header which has to be (un)set, but
I can't find any.<br>
Multiple via ways are not yet supported, but partly verified
to be correct.<br>
Maybe I'll look at that when we see an effect on routing for a
single via way.<br>
<br>
@Steve: Do you see any effect of them in your maps? <br>
If yes, what might be wrong with the data written by mkgmap?<br>
<br>
Gerd<br>
<br>
</div>
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<pre class="ecxmoz-signature">--
keep on biking and discovering new trails
Felix
openmtbmap.org & <a class="ecxmoz-txt-link-abbreviated" href="http://www.velomap.org" target="_blank">www.velomap.org</a></pre>
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