Hi Carlos, thanks for the quick feedback. I just noticed that I forgot to remove a debug output. r2737 is available here: http://files.mkgmap.org.uk/download/153/mkgmap.jar Gerd Carlos Dávila-2 wrote
El 05/10/13 11:56, GerdP escribió:
Hi all,
I think I understand now most of the miracles related to short arcs and I am pretty sure that we can solve the known problems without adding source complexity.
1) In 2009 Mark Burton added the remove-short-arcs option with r1049. 2) With r1060 he added the option to pass a parameter giving the minimum arc length to fix problems like "disappearing ways". Unfortunately, he missed the real reason for the error, which IMHO was the buggy implementation of --link-pois-to-ways and --remove-short-arcs regarding the highway count causing more or less unpredictable results. 3) For four years people wondered what value to use as a change of the value was likely to "fix" a known routing error while also adding other "not yet known" errors.
Today I've committed r2736. I my eyes (presuming all coding errors are fixed now) the only usable value is --remove-short-arcs=0, everything else is likely to create problems like distorted lines, wrong routing (cars routed through footways) and wrong exit hints in roundabouts. The only advantage that I see is a slightly smaller number of nodes, but this will soon be fixed when the mergeroads branch is merged to trunk, but I might have missed something.
So, in short: All those that are using mkgmap to create routable maps, please try r2736 with --remove-short-arcs=0 (binary is here http://files.mkgmap.org.uk/download/152/mkgmap.jar) or use the mergeroads branch (requires style changes) If you find any problem regarding routing, please let us know and try to provide details.
If I hear no complains until Oct 15, I like to change the default back to 0 and print a warning if a different value is used. If --remove-short-arcs=0 works fine for everybody, we should remove the option.
Gerd Thanks for the deep work you have done on it Gerd. I have a roundabout test case where routing have been failing for a long time. With r2736 routing works fine with remove-short-arcs=0 and without any value (default), but the shape of the roundabout is a circle with 0 and something like a start with default, so much better with 0.
mkgmap-dev mailing list
mkgmap-dev@.org
-- View this message in context: http://gis.19327.n5.nabble.com/short-arcs-demystified-please-try-value-0-tp5... Sent from the Mkgmap Development mailing list archive at Nabble.com.