[OSM-dev] Defining the area of a country / What country is a LatLon in.

Marcus Wolschon Marcus at Wolschon.biz
Fri Nov 23 07:29:44 GMT 2007


-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1


Update:

I'm getting a bit frustrated because I cannot make progress
on the address-search nor on the routing-metrics without this,
so I'm going to implement a function to download the border-
parts by tag-name and try to automatically sort and join them
to form polygons locally. Then build inner/outher polygons
with less level of detail down to having only a bounding-box
and store these locally.
I'll make the code avaliable in the wiki and probably also
as a web-service.

Frederik Ramm schrieb:
> Hi,
> 
> Then why can't you download the planet every now and then and update
> your borders ;-)

Simple.
The planet is multiple gigabyte. Does your commercial navigator
on a n-GB SD-card force you to download XX GB every 2 month?
I can let people download what maps they need for getting from
A to B without having them download maps they don't need and thus
probably don't want on their disks/flash-cards.
I'm trying the move from an experimental "yes, in theory we can
route on OSM" to actual in-car -navigation here to show the benefit
of the map to people and thus get more people interested in the project.

> No honestly, you're asking for more than OSM can deliver. Go get your
> country boundaries elsewhere (maybe geonames.org)? Firstly, it is not
> yet clear how borders are going to be mapped (some say that relations
> might be used for this). Current border mapping is (as you may have
> found out yourself) not really compatible, planet-wide, and I don't
> think that trying to forge some sort of half-baked rule about how we're
> going to do it will help you, because as soon as you've implemented that
> it is going to change. Currently, too few people are concerned about
> borders to give that a lot of thought.

Some day we have to care about it and we already have quite some
nationality-specific data in there. As I see it we should find
a consensus as soon as possible because the later we get one the
more work it will be.
As far as speed-limits are concerned everyone doing routing on
OSM needs this question answered by the map the moment they are
to display a travel-time outside their own country.

We found a map-wide concensus on how to map the completely different
street-classifications of every country in a single schema. There is
only one type of country-border on this planet and no question about
what a country is. The only thing needed is a proposed tagging-rule
for a feature we are already mapping. We do have all the borders here
from the automatic import and the oceans are the only place where they
need to be closed.

> Secondly, even if it *were* clear how to map borders, it would take a
> good while until even the European (not to speak of African etc.)
> borders were even close to forming polygons you could use - you'd be
> guessing heavily most of the time.

We don't have terribly many borders in this world and at least
europe is in our map. I could probably join them in a weekend and
we would then have it.


> 
> You will achieve much better results by using available data from other
> sources - for at least half a year, if not longer.

That would be quite sad given that it is data we do have and just
can't agree on how to search it.

Marcus
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.6 (GNU/Linux)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org

iD8DBQFHRoFof1hPnk3Z0cQRAnmKAJsGoaWcwUYuW3D++ZKj04bEr9PtAACePify
lw3GzXypsi4tkRLDl4cmrl0=
=6Qxd
-----END PGP SIGNATURE-----




More information about the dev mailing list