[OSM-talk] administrative boundaries and is_in

[80n]

On Jan 10, 2008 9:11 AM, Robin Paulson <robin.paulson at gmail.com> wrote:

> On 10/01/2008, Michael Collinson <mike at ayeltd.biz> wrote:
> > >which seems counter-intuitive, not to mention requiring huge amounts
> > >of work. do we set this for every item - roads, churches,
> > >supermarkets,....thousands of other items?
> > >is there anything underway to enable OSM to calculate where an object
> > >is, based upon knowledge of administrative boundaries - after all,
> > >they are only a polygon-shaped bounding box?
> >
> > Yes, sort of.  But the other way around, I am working on deriving
> > administrative boundaries from "is_in" and "place" tags. *If* it
> > works, the answer to your main question would be to randomly use
> > is_in tags on low level items such as roads and churches and let the
> > computer work out a boundary around them.  I should be able to report
> > back in February.
>
> sorry mike, i'm sure you've put a lot of work in, but that sounds even
> more backwards, and very difficult to control well - i foresee a lot
> of fudging to make it work in a lot of areas.
>
> the boundary data should be relatively easy to come by, and require a
> *lot* less points to be drawn/edited, than your method. plus, your
> method is never going to be one hundred percent perfect. for example,
> what happens in areas of open country side, with no POIs to mark, when
> the boundary changes direction - something that will happen a lot?
> and what when a place is in two administrative boundaries? there are
> fairly major cities that straddle for instance state lines in the US.
> i think arkansas may be one?
>
> but i guess itches should be scratched....something will doubtless
> come from this, whether unintended or not. ok, it'll be interesting to
> see your results
>

Having multiple ways of achieving the same (or similar) results is not a bad
thing.  Each will have it's own strengths an weaknesses.

80n




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