[mkgmap-dev] [Patch] improve handling of only-restrictions with via ways

Thu Oct 10 17:14:29 BST 2019

Hi Gerd

No problems that I can see - but very difficult to test.

I've run 'british-isles-latest' with the patch.

There is 1 extra error message that a duplicate, ie I get:

SEVERE (RoadNetwork): 74220083.osm.pbf: Turn restriction
(only_straight_on) http://www.openstreetmap.org/relation/8727983 (at 
http://www.openstreetmap.org/?mlat=51.541969&mlon=0.004312&zoom=17)
can't locate arc from 'via' node at 
http://www.openstreetmap.org/?mlat=51.541949&mlon=0.004060&zoom=17 to
next 'via' node on way 642330324

SEVERE (RoadNetwork): 74220083.osm.pbf: Turn restriction
(only_straight_on) http://www.openstreetmap.org/relation/8727983 (at 
http://www.openstreetmap.org/?mlat=51.541969&mlon=0.004312&zoom=17)
can't locate arc from 'via' node at 
http://www.openstreetmap.org/?mlat=51.541949&mlon=0.004060&zoom=17 to
next 'via' node on way 642330324

Whereas before I only got this message once. This is a restriction with
3 via's.
(I get 12 other messages relating to restrictions)

For all but this tile, the .img files are the same size and, picking a
few examples, the NET and NOD parts are identical.

For this tile the NET parts are identical but the NOD is not really
comparable because of different sizes / offsets.

pre-patch size:  10102784 Oct 10 11:52 74220083.img
post-patch size: 10104832 Oct 10 15:58 74220083.img

Ticker

On Thu, 2019-10-10 at 09:49 +0000, Gerd Petermann wrote:
> Hi all, 
> 
> in http://gis.19327.n8.nabble.com/Turn-Restrictions-using-three-ways-
> design-guide-for-OSM-mappers-tp5949183.html
> Thanks to blc I've learned that only_* restrictions with via ways
> should be interpreted a bit different. As you might know the Garmin
> IMG format only has restrictions of type "no", so mkgmap has to
> translate "only" restrictions to a list of "no" restrictions. For
> those "only" restrictions the current code in version r4295 checks
> the roads connected to  (the last) "via"-node and adds a "no"
> restriction for all ways except the "to"-way. 
> The meaning of an "only" restriction with "via"-way(s) is a bit
> different . I means something like "once you have reached the node
> that connects the "from"-way with the (first) "via"-way travelling on
> the "from" way you MUST use the route described in the restriction
> relation unless you have reached the "to" way.
> So, mkgmap must add restrictions for each route node on the "via"
> -way(s), not only the last.
> 
> The patch implements this and no longer prints a warning for "only"
> -restrictions with "via" ways (severity was changed from warning to
> information).
> 
> I've uploaded a binary here:
>  http://files.mkgmap.org.uk/download/452/mkgmap.jar
> 
> If I hear no complains I'll commit this patch next Monday.
> 
> Gerd
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