problem with specific type of polygon

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Jarosław Jasiewicz

problem with specific type of polygon

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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
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Roger Bivand

Re: problem with specific type of polygon

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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
> _______________________________________________
> grass-stats mailing list
> [hidden email]
> http://lists.osgeo.org/mailman/listinfo/grass-stats
>

--
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: [hidden email]

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grass-stats mailing list
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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
Jarosław Jasiewicz

Re: problem with specific type of polygon

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Roger Bivand pisze:

> 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
>> _______________________________________________
>> grass-stats mailing list
>> [hidden email]
>> http://lists.osgeo.org/mailman/listinfo/grass-stats
>>
>
Yes it is it!

Thank you very much
Jarek
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