computing polygons from a centroid point distribution

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computing polygons from a centroid point distribution

Patrick Giraudoux
Hi,

Given a spatial point distribution in a two dimensional space, I wonder
if there is a function in R that could make a polygon partition of the
two dimensional space, with each point as centroid of each polygon ?

Any suggestion about package(s) and function(s), if any, welcome,

Best,

Patrick

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Re: computing polygons from a centroid point distribution

Ben Madin
Patrick,

On 20/12/2011, at 2:40 PM, Patrick Giraudoux wrote:

> Given a spatial point distribution in a two dimensional space, I wonder if there is a function in R that could make a polygon partition of the two dimensional space, with each point as centroid of each polygon ?
>
> Any suggestion about package(s) and function(s), if any, welcome,

> library(deldir)
> ?deldir

might be what you are after?

cheers

Ben

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Re: computing polygons from a centroid point distribution

Patrick Giraudoux
Le 20/12/2011 07:53, Ben Madin a écrit :

> Patrick,
>
> On 20/12/2011, at 2:40 PM, Patrick Giraudoux wrote:
>
>> Given a spatial point distribution in a two dimensional space, I wonder if there is a function in R that could make a polygon partition of the two dimensional space, with each point as centroid of each polygon ?
>>
>> Any suggestion about package(s) and function(s), if any, welcome,
>> library(deldir)
>> ?deldir
> might be what you are after?
>
> cheers
>
> Ben
>
>

Yes ! exactly what I needed. Missed that it could have been properly
called "tesselation", rather than to use winding explanations...

Many thanks,

Patrick

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Re: computing polygons from a centroid point distribution

Rolf Turner

You should be aware that the ***centroid*** of a Dirichlet/Voronoi tile is
***NOT*** in general the point determining that tile.

I do not believe that your original question, as posed (in terms
of centroids) actually has a solution.

     cheers,

         Rolf Turner

On 20/12/11 21:55, Patrick Giraudoux wrote:

> Le 20/12/2011 07:53, Ben Madin a écrit :
>> Patrick,
>>
>> On 20/12/2011, at 2:40 PM, Patrick Giraudoux wrote:
>>
>>> Given a spatial point distribution in a two dimensional space, I
>>> wonder if there is a function in R that could make a polygon
>>> partition of the two dimensional space, with each point as centroid
>>> of each polygon ?
>>>
>>> Any suggestion about package(s) and function(s), if any, welcome,
>>> library(deldir)
>>> ?deldir
>> might be what you are after?
>>
>> cheers
>>
>> Ben
>>
>>
>
> Yes ! exactly what I needed. Missed that it could have been properly
> called "tesselation", rather than to use winding explanations...
>
> Many thanks,
>
> Patrick
>
> _______________________________________________
> R-sig-Geo mailing list
> [hidden email]
> https://stat.ethz.ch/mailman/listinfo/r-sig-geo

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Re: computing polygons from a centroid point distribution

Patrick Giraudoux
Le 23/12/2011 02:41, Rolf Turner a écrit :

>
> You should be aware that the ***centroid*** of a Dirichlet/Voronoi
> tile is
> ***NOT*** in general the point determining that tile.
>
> I do not believe that your original question, as posed (in terms
> of centroids) actually has a solution.
>
>     cheers,
>
>         Rolf Turner



Thanks for this info. Now I realize that my question was wrongly
formulated. A tesselation based on spatial points was enough for what I
wanted to do.

Best,

Patrick



>
> On 20/12/11 21:55, Patrick Giraudoux wrote:
>> Le 20/12/2011 07:53, Ben Madin a écrit :
>>> Patrick,
>>>
>>> On 20/12/2011, at 2:40 PM, Patrick Giraudoux wrote:
>>>
>>>> Given a spatial point distribution in a two dimensional space, I
>>>> wonder if there is a function in R that could make a polygon
>>>> partition of the two dimensional space, with each point as centroid
>>>> of each polygon ?
>>>>
>>>> Any suggestion about package(s) and function(s), if any, welcome,
>>>> library(deldir)
>>>> ?deldir
>>> might be what you are after?
>>>
>>> cheers
>>>
>>> Ben
>>>
>>>
>>
>> Yes ! exactly what I needed. Missed that it could have been properly
>> called "tesselation", rather than to use winding explanations...
>>
>> Many thanks,
>>
>> Patrick
>>
>> _______________________________________________
>> R-sig-Geo mailing list
>> [hidden email]
>> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>
>

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