> > > I'm aware of the concept that the earth is not flat. > > But... This is a two dimensional map. IFAIK there is no 3d data. The PoV > of viewing the OSM data via the likes of Mapnik is always through the > surface of the earth to the centre of the earth. Therefore a line such > as this Oz highway is, when viewed in a map, going to be straight. >
ah, not exactly depending on your projection and its distortions (all projections have distortions) a straight line on earth can be represented as a curved line on a map. Eg Air navigation east coast north america to europe. This is long enough that shown on a Mercator projection the straight line which the pilot flies is shown as a curve - because in 3D it is a curve. It is known as a Great circle. http://mathworld.wolfram.com/GreatCircle.html "A great circle becomes a straight line in a gnomonic projection " _______________________________________________ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
