[Gvsig_english] calculating centre points of polygon and ascribing coordinates

[Simon Cropper (Botanicus Australia Pty Ltd)]

Wolfgang,

I stated the on-line manual did not have the information about the "Add 
geometry info".

I eventually found it here (in spanish) under "add geographic 
information to the layer" (Agregar información geográfica a la capa)...

<http://translate.google.com.au/translate?hl=en&sl=es&u=http://www.gvsig.org/web/docusr/new-functionalities-gvsig-1-9&ei=BTYLS-C8LdKDkAXYrv2rAw&sa=X&oi=translate&ct=result&resnum=4&ved=0CBUQ7gEwAw&prev=/search%3Fq%3Dhttp://www.gvsig.org/web/docusr/new-functionalities-gvsig-1-9%26hl%3Den%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-GB:official%26hs%3DDek%26num%3D100> 


Cheers Simon

Simon Cropper
Botanicus Australia Pty Ltd
PO Box 160, Sunshine, Victoria 3020.
P: 9311 5822. M: 041 830 3437.
mailto: scropper at botanicusaustralia.com.au 
<mailto:scropper at botanicusaustralia.com.au>
web: www.botanicusaustralia.com.au <http://www.botanicusaustralia.com.au>



Wolfgang Qual wrote:
> Hi Simon,
> well, I browsed a little bit and found an answer:
> you can export your polygon layer to an annotation layer (export to...
> annotation). Then edit this annotation layer (add x- and y-coordinates
> using the field calculator). 
>
> best,
> wolfgang
> Am Mittwoch, den 25.11.2009, 00:20 +1100 schrieb Simon Cropper
> (Botanicus Australia Pty Ltd):
>   
>> Hi,
>>
>> I have found some answers.
>>
>> First X, Y can be extracted with the field calculator using the 
>> functions x() and y().
>>
>> Sextante can be used to extract the centre point of a polygon.
>>
>> This aside is there any way of consolidating these tasks? Can you 
>> calculate the centre point of a polygon in gvSIG?
>>
>> Cheers Simon
>>
>> Simon Cropper
>> Botanicus Australia Pty Ltd
>> PO Box 160, Sunshine, Victoria 3020.
>> P: 9311 5822. M: 041 830 3437.
>> mailto: scropper at botanicusaustralia.com.au 
>> <mailto:scropper at botanicusaustralia.com.au>
>> web: www.botanicusaustralia.com.au <http://www.botanicusaustralia.com.au>
>>
>>
>>
>> Simon Cropper (Botanicus Australia Pty Ltd) wrote:
>>     
>>> Hi Everyone,
>>>
>>> Can someone tell me if gvSIG can be used to establish the centre point 
>>> of a polygon?
>>>
>>> ... and subsequently place the X and Y coordinates in fields in the 
>>> attribute table of the polygon shapefile?
>>>
>>> ... or alternatively create a point file representing the centrepoint 
>>> and be able to assign the XY values to that shapefile.
>>>
>>> What I regularly do in alternative programs (OpenJUMP, Kosmo, Sextante) 
>>> is create a point file showing the centrepoint of a set of polygons 
>>> (usually representing the sites I have surveyed) and then using ArcView 
>>> assign the XY coordinate of the points to the northing+easting fields. 
>>> Reproject into Lat-Long and repeat. These coordinates are used to report 
>>> the sites locations to government agencies.
>>>
>>> How would you do this in gvSIG?
>>>
>>> Can you use Jpython to do this?
>>>   
>>>       
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