[mkgmap-dev] Reported similar arcs are not so similar

Fri Jan 8 21:47:07 GMT 2016

Some osmers who work fixing errors in OSM data using the files I serve 
have reported a lot of cases of supposed similar arcs which are not 
errors, like the following examples:
(http://www.openstreetmap.org/browse/way/47972506) and 
(http://www.openstreetmap.org/browse/way/21690948)
(http://www.openstreetmap.org/browse/way/152931346) and 
(http://www.openstreetmap.org/browse/way/327519978)
(http://www.openstreetmap.org/browse/way/163137843) and 
(http://www.openstreetmap.org/browse/way/297772507)
According to an old message from Mark Burton [1], ways with same start 
point, end point and length are reported as similar arcs by 
--report-similar-arcs option, even if they don't overlap. The ones above 
may meet those conditions, but it would be nice if not overlapping ways 
are omitted. Perhaps an extra check for a third point in common would help.
[1] http://www.mkgmap.org.uk/pipermail/mkgmap-dev/2010q1/006709.html