[GRASS-stats] problem with specific type of polygon

[Roger Bivand]

On Thu, 9 Apr 2009, Jarek Jasiewicz wrote:

> Hi
> it is difficult to reproduce on spearfish, because there are no data like 
> this
>
> I vextorised watershed file and at the end of some watershed I have 
> sutructure like on picture below (rather tipical for watershed):
>
>                               |
>                               |
>                          +  |                 __________|_
>                               |_|_
>                                  |_|_
>                                     |_|_
>                                        |_|
>
>
> Addationaly every square on right-down "stream" has his own centeroid but 
> with the same cateogry like main centeroid
>
> I import these data to R with readVECT6 and I have more object than shoud be, 
> because every square became a separtate vector with his own attributes (some 
> of atrributes are multipied).
>
> In grass I can treat such group as one object by its category number but in 
> R? How to force R to treat these group of polygons as one obiect

Jarek:

An attempt is made in the code with the remove.duplicates= argument. In 
addition for polygons, you can try unionSpatialPolygons() in maptools to 
force the objects belonging together into the same Polygons object.

Hope this helps,

Roger

>
> Jarek
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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