[R-sig-Geo] Testing if a point-pattern is on a regular grid

[Hisaji ONO]

Hello.

 I have an idea using Thiessenn or voronoi by tripack.

 Extending this "points2grid()" method for grid polygon
data will make calculation of spatial weight matrices of
spdep better?


 Regards   

--- Roger Bivand <Roger.Bivand at nhh.no> wrote:

> On Wed, 6 Jan 2010, Pierre Roudier wrote:
> 
> > Dear list,
> >
> > I'm looking for an easy way to test if a point
> pattern (I got a data
> > frame of x and y coordinates) is on a regular grid
> or not.
> >
> > I'm aware of the gridded() function in sp(), but
> this function is
> > devoted to assign rather than to test, as far as I
> know. I'm pretty
> > sure there's an easy way to do that though....
> 
> Use try(points2grid()) - if this returns an object
> of class "try-error", 
> the points do not lie on a grid.
> 
> Roger
> 
> >
> > Any suggestions ?
> >
> > Thanks,
> >
> > Pierre
> >
> > _______________________________________________
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> > R-sig-Geo at stat.math.ethz.ch
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> >
> 
> -- 
> Roger Bivand
> Economic Geography Section, Department of Economics,
> Norwegian School of
> Economics and Business Administration, Helleveien
> 30, N-5045 Bergen,
> Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
> e-mail: Roger.Bivand at nhh.no
> 
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