distance and convex hull for multi-geometries

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distance and convex hull for multi-geometries

Barend Gehrels
Hi,

I implemented the distance algorithm for multi geometries
(single-to-multi, multi-to-multi). This is to verify this discussion:
http://article.gmane.org/gmane.comp.lib.boost.devel/187452/match=distance 
(I need it next week in BoostCon).
Distance is not yet completed but these ~100 lines of code cover 75% of
the matrix of 36 possibilities (6x6, point-point, point-linestring, etc)...
Future improvement: they would probably profit from a spatial index on
multi-s.

Furthermore I also implemented convex hull for multi-points (email
Nicolas) and multi-linestrings/multi-polygons.
I therefore also created a tiny utility "as_range" which can see the
exterior ring of a polygon as a range. Having as_range, polygons don't
have to be handled differently.

Regards, Barend



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distance and convex hull for multi-geometries

Mateusz Loskot
Administrator
Barend Gehrels wrote:
> Hi,
>
> I implemented the distance algorithm for multi geometries
> (single-to-multi, multi-to-multi).

Cool!

> This is to verify this discussion:
> http://article.gmane.org/gmane.comp.lib.boost.devel/187452/match=distance
> (I need it next week in BoostCon).
> Distance is not yet completed but these ~100 lines of code cover 75% of
> the matrix of 36 possibilities (6x6, point-point, point-linestring, etc)...
> Future improvement: they would probably profit from a spatial index on
> multi-s.

Wow! That's a nice number of possibilities :-)

> Furthermore I also implemented convex hull for multi-points (email
> Nicolas) and multi-linestrings/multi-polygons.
> I therefore also created a tiny utility "as_range" which can see the
> exterior ring of a polygon as a range. Having as_range, polygons don't
> have to be handled differently.

Nice idea.

Unfortunately, I don't have time to test it at this moment,
but will try to do it in near future.

Best regards
--
Mateusz Loskot, http://mateusz.loskot.net
Charter Member of OSGeo, http://osgeo.org
--
Mateusz Loskot
http://mateusz.loskot.net