I believe Muki Haklay's comparison of OSM and OS used this method: buffer two lines into polygons, compare the ratio of their intersection and union. The buffering is done in mercator coordinates so it's conformal. I use a technique like this in Skeletron to find simple centerlines for single and dual carriageways, works great.
-mike. On Jan 4, 2013, at 6:47 AM, David Prime wrote: > Construct a polygon from the two lines and calculate the area inside? Have > some magic number denoting an acceptable length/area ratio that scales the > limit appropriately. There's a few nasty edge cases, though. > > > On Fri, Jan 4, 2013 at 2:44 PM, Paweł Paprota <ppa...@fastmail.fm> wrote: > Hi Andrzej > > On 01/04/2013 03:37 PM, andrzej zaborowski wrote: > > If the number of nodes in a way didn't change you could optimize by just > comparing them coordinate by coordinate. > > I was thinking you could take the maximum of every node's distance > from the other way. It should yield the same metric as ST_Buffer > would. > > > I tried that by using ST_MaxDistance but it fails for some cases where the > maximum distance is actually quite large even though the linestrings are near > each other. > > Paweł > > > _______________________________________________ > dev mailing list > dev@openstreetmap.org > http://lists.openstreetmap.org/listinfo/dev > > _______________________________________________ > dev mailing list > dev@openstreetmap.org > http://lists.openstreetmap.org/listinfo/dev ---------------------------------------------------------------- michal migurski- contact info and pgp key: sf/ca http://mike.teczno.com/contact.html _______________________________________________ dev mailing list dev@openstreetmap.org http://lists.openstreetmap.org/listinfo/dev
