[Tagging] Race track

John Smith deltafoxtrot256 at gmail.com
Sun Jan 31 16:36:27 GMT 2010

On 1 February 2010 02:24, Anthony <osm at 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

> 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

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