[OSM-dev] Advice sought on polygon-with-hole drawing

Andy Allan gravitystorm at gmail.com
Mon Mar 17 12:33:15 GMT 2008


On Fri, Mar 14, 2008 at 10:43 AM, Robert (Jamie) Munro
<rjmunro at arjam.net> wrote:

>  Yes. That is what I am saying. 1 simple rule:
>
>  *All* areas should be colour on the right (i.e. clockwise)

No chance. This is a completely terrible idea. It makes it harder for
newbies, who have to know to check and change the "direction" of the
ways of an area, which is an entirely pointless process from their
point of view and will probably make no sense to them.

Direction is important for one-way roads but shoudn't be for areas.
Coastline is an understandable exception.

Cheers,
Andy

>  It's simple, it's validatable (albeit the current JOSM validator get's
>  it wrong), it means that coastline is not an exception, it makes the
>  maths simpler. It might even mean that you don't need relationships to
>  associate inner and outer -  Any system that gets 1 segment of an area
>  should be able to know which side of that segment the feature is on.
>
>
>  | Also, my idea would allow a way to serve as an "inner" member of one
>  | multipoly at the same time as as an "outer" member of another; I think
>  | you couldn't get that with evenodd.
>
>  That's really ugly. There should be 2 ways. They can share nodes if that
>  ~ is wanted. If you really want to use only one way, then you could put a
>  direction=-1 tag or something in the relationship that defines the
>  tagging for the inner area, but I still don't like that. I think that if
>  the edge of an area crosses through something you should know what is on
>  each side of it without having to consider special tags for exceptional
>  cases.
>
>
>  Robert (Jamie) Munro
>  -----BEGIN PGP SIGNATURE-----
>  Version: GnuPG v1.4.6 (Darwin)
>  Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org
>
>  iD8DBQFH2lboz+aYVHdncI0RAgafAKCJBEW2LG9F6Rczm4gp+EU8/8Qt+gCgpMqE
>  M1p5oF0jvynuW31P8KNnu7o=
>  =c5+U
>  -----END PGP SIGNATURE-----
>
>
>
>  _______________________________________________
>  dev mailing list
>  dev at openstreetmap.org
>  http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/dev
>




More information about the dev mailing list