[OSM-talk] how big are ways?

[Dave Stubbs]

On 26/11/2007, Paul Fox <pgf at foxharp.boston.ma.us> wrote:
> i wrote:
>  > okay -- silly sounding question, i know.
>  >
>  > but i'm wondering if there are any limits, imposed by validation,
>  > policy, or simply peer pressure, on either the length, or the
>  > geographic area covered by any single way.
>
> missing background, to clarify:  the question is based on
> thinking about heuristics for a renderer -- not as a basis for
> surveying or map editing.
>
> (in other words, i'm asking more about the length of current ways
> than about guidelines to follow when creating ways.)
>


No limits by validation.

By peer pressure it's generally polite to split ways which have lots
and lots of nodes or are really long. But as you can see from the
following stats, this isn't always followed.

>From the most recent planet dump I can tell you that way length for
things identified by the osm2pgsql program as lines, are very roughly
(not sure the projection is right):
- maximum: 2000km (the Rotterdam-Torshavn ferry route, in just 85 nodes)
- mean: 1km
- min: virtually zero

only about 10 ways are more than 1000km ish (a couple of trunk roads
in Russia (M-4, M-5), the Argentine-Chile border, lake Nasser, the
Indus river, and a railway)
only about 2k ways are more than 100km ish
about 120k ways are more than 10km ish
about 1.5m ways are more than 1km ish
leaving about 6.9m smaller than 1km ish

In terms of number of nodes:
- maximum: 6200 nodes (148th Street, Brown Country, South Dakota)
- mean: 12 nodes

There are 636 lines which have more than 1000 points, with 68 having
more than 2000. These ways should probably be split as they'll
probably cause problems if they are not.

I hope that helps.

Dave