[Manifold-l] merge points to areas

[Martin Roseveare]

Hadn't thought of that, however, contours seems the easiest way to go and
the smoothing you get with contours does produce a slightly nicer-looking
drawing for the client as well.

I will look into the spatial SQL option though as it might better suit my
long-term goal. Thanks for the pointer.


Martin Roseveare
Senior Geophysicist

 
Web: www.archaeophysica.co.uk
Phone: +44 (0) 1989 730 564
Fax: +44 (0) 7050 369 790

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> -----Original Message-----
> From: Simon Greener (SpatialDB Advisor)
> [mailto:spatialdbadvisor at netspace.net.au]
> Sent: 10 October 2007 10:00
> To: Bob Heitzman; m.roseveare at archaeophysica.co.uk
> Cc: manifold-l at directionsmedia.net
> Subject: Re: [Manifold-l] merge points to areas
> 
> On Wed, 10 Oct 2007 06:53:08 +1100, Bob Heitzman <rheitzman at gmail.com>
> wrote:
> 
> > I have a drawing containing points on a common grid and in dense groups,
> > like blobs of mould I suppose, for want of a better description.
> >
> > I need to be able to coalesce these into areas, one per group. In
> > principle
> > it's just a complex hull function, however, I want the complex hull of
> > each group and not the whole drawing. If there were a small number of
> > groups I could select each by hand, but there are several hundred...
> >
> > Any suggestions as to how to automate this?
> 
> What defines a group? An attribute or the fact that they are "spatially
> correlated"?
> 
> If the latter, have you considered converting the drawing to a surface
> (via kriging or some such) then identifying the groups by spatial sql (eg
> one of the raster extension functions such as HeighMaj with a 9x9 window)?
> 
> regards
> Simon
> --
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