Error - zero length arc
I have a problem with a zero length arc (mkgmap 1107): SCHWERWIEGEND (RoadNetwork): Road null (OSM id 34881225) contains zero length arc SCHWERWIEGEND (RoadNetwork): http://www.openstreetmap.org/?lat=47.83413&lon=11.70958&zoom=17 This is a strange railway=platform. It is mapped like a very narrow 'area'. I have set the flag --remove-short-arcs and this road is also not on a tile border. (I tried the same area with mkgmap 1092 and the map was created without an error message.) Is there a problem with the remove-short-arcs algorithm? (I can change the OSM data but I'd prefer to have an mkgmap version without error message for this kind of way). Regards, Rudi
Hi Rudi,
I have a problem with a zero length arc (mkgmap 1107):
SCHWERWIEGEND (RoadNetwork): Road null (OSM id 34881225) contains zero length arc SCHWERWIEGEND (RoadNetwork): http://www.openstreetmap.org/?lat=47.83413&lon=11.70958&zoom=17
This is a strange railway=platform. It is mapped like a very narrow 'area'. I have set the flag --remove-short-arcs and this road is also not on a tile border. (I tried the same area with mkgmap 1092 and the map was created without an error message.)
Is there a problem with the remove-short-arcs algorithm? (I can change the OSM data but I'd prefer to have an mkgmap version without error message for this kind of way).
Something that's bugging me about this example is that it's a railway platform and shouldn't be routable anyway. Have you styled it into a highway of some kind? If so, that could be the root of the problem. Anyway, I can't think any more tonight, I'll look again in the morning. Cheers, Mark
Hi Mark,
Something that's bugging me about this example is that it's a railway platform and shouldn't be routable anyway. Have you styled it into a highway of some kind? If so, that could be the root of the problem.
Yes, I have a custom style file and I want to see the platform as a footway (routing enabled): railway=platform {set ...} [0x0d road_class=0 road_speed=0 level 0] Regards, Rudi
Hi Rudi,
Yes, I have a custom style file and I want to see the platform as a footway (routing enabled): railway=platform {set ...} [0x0d road_class=0 road_speed=0 level 0]
OK - I have just processed that map using a similar rule and I don't get the short arc message. Sorry, I don't know what the issue is here. Are you sure you're using the latest mkgmpa? BTW - the remove short arc processing is done before the style file processing and it is only applied to highways and ferry routes so if the style file makes something else into a road (from the routing point of view) then it will not have had its arcs tweezed. This way of doing things is unlikely to change anytime soon. Cheers, Mark
On Mon, Jul 27, 2009 at 08:08:59AM +0100, Mark Burton wrote:
BTW - the remove short arc processing is done before the style file processing and it is only applied to highways and ferry routes so if the style file makes something else into a road (from the routing point of view) then it will not have had its arcs tweezed. This way of doing things is unlikely to change anytime soon.
What are the implications of having short arcs? Routing unable to follow the way across the short arc? What if there is an improvised short wooden bridge on a forest path that crosses a very narrow waterway? Could you please use . as the decimal separator in the error message? I am getting messages that look like this: SEVERE (RoadNetwork): http://www.openstreetmap.org/?lat=65,01078&lon=25,48210&zoom=17 In LANG=fi_FI (and in many other European languages, including German, for that matter), the decimal separator is , and the thousands separator is . or a space. JOSM will ignore the URL until I manually replace the commas with dots. Best regards, Marko
Hi Marco,
What are the implications of having short arcs? Routing unable to follow the way across the short arc? What if there is an improvised short wooden bridge on a forest path that crosses a very narrow waterway?
You get a short arc wherever two (directly connected) nodes are so close together that their coordinates are the same. As you know, the resolution is just over 2m so any (connected) nodes that are less than approx 2.5m apart will need to be merged to avoid having short arcs. The GPS and mapsource don't appear to like short arcs so they have to be weeded out otherwise the routing gets broken.
Could you please use . as the decimal separator in the error message? I am getting messages that look like this:
SEVERE (RoadNetwork): http://www.openstreetmap.org/?lat=65,01078&lon=25,48210&zoom=17
In LANG=fi_FI (and in many other European languages, including German, for that matter), the decimal separator is , and the thousands separator is . or a space. JOSM will ignore the URL until I manually replace the commas with dots.
That should now be fixed. Cheers, Mark
participants (3)
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Mark Burton -
Marko Mäkelä -
Rudi