On 1 February 2010 02:24, Anthony <o...@inbox.org> wrote: > I think railway tracks have constant widths. Otherwise the trains would > have a lot of problems.
Same with road ways funnily enough, the widths are generally consistent, the number of tracks running in parallel isn't consistent however... > I don't understand the question. To make that image, they didn't need to create an area, they estimated the lane widths... > Why is raster mapping more accurate? I thought the point of vector graphics > was that they were *more* accurate. Nothing is going to be 100% accurate, How can vector graphics ever be more accurate than raster? Vector graphics allow you to use many many less points to roughly describe the same thing. > Limited value besides... Fine, at least you agree it is of some value. To surveyors, sure, but their needs are a lot more accurate than you will plot out in vector. > You can if you designate one way as left and one way as right. I do not > mean for "area" to imply "single closed way". Which is attempting to raster vector plots, but vector graphics aren't the best tool for the job, aerial imagery on the other hand is. > Not like roadways. Trains can only drive along tracks. Those tracks are a > fixed distance apart. It's nothing like a highway. Sure, cars can change lanes much easier, but the idea is still the same, and in fact the width of wheels of both cars and trains date back to roman times, the romans built road ways for their chariets. Railways might be more fixed, but tains can flip between tracks if the junctions are right, road ways have juctions for similar reasons, so they share a lot in common. > I'll stick with the specific solution I've already worked out, rather than > "some kind of cascade method". Except it's not really a solution, it's a method of trying to rasterise using vector based software. I'd hate to see them try to use areas to map road ways in Japan or any other highly complicated interchanges for that matter, it would end up an utter mess in a very short amount of time. We a proper method to map lanes. I've explained my thoughts on this to the main talk list in depth, however I can rehash it in this thread too if you want, the idea is ways are really a grouping of lanes, which make ways a special type of relation. _______________________________________________ Tagging mailing list Tagging@openstreetmap.org http://lists.openstreetmap.org/listinfo/tagging
