[Gvsig_english] clean polygon? Issue with layers importedfromOracle Spatial

Francisco José Peñarrubia fpenarru at gmail.com
Wed Feb 17 16:58:33 CET 2010


Hola Juan.

You are right, internally gvSIG don't need to check it, but we should 
write it with the correct orientation (and fix it if needed as Oracle 
Writer does). So, ShapeWriter should test the orientation of polygons, 
as ShapeFile format especifies. By the way, is my fault ;-)

http://www.esri.com/library/whitepapers/pdfs/shapefile.pdf

Saludos.

Fran.

Juan Lucas Dominguez Rubio escribió:
> Hello,
>  
> If I understood it well, gvSIG does not use the 
> clockwise/counter-clockwise rule to decide what is inside and what is 
> outside. It inherits the so-called 'winding rule' from AWT:
>  
> http://developer.classpath.org/doc/java/awt/geom/GeneralPath.html
>  
> That's why the Oracle Spatial writer checks that the orientation 
> respects the Oracle rule (outer ring is counter-clockwise), but does 
> not reverse it when you add an Oracle Spatial layer to a gvSIG view 
> (because the Oracle Spatial orientation is also valid using the 
> winding rule).
>  
> Regards,
>  
>  
> Juan Lucas Domínguez Rubio
> ---
> Prodevelop SL, Valencia (España)
> Tlf.: 96.351.06.12 -- Fax: 96.351.09.68
> http://www.prodevelop.es <http://www.prodevelop.es/>
> ---
>
> ------------------------------------------------------------------------
> *De:* gvsig_internacional-bounces at listserv.gva.es en nombre de 
> Wolfgang Qual
> *Enviado el:* mié 17/02/2010 16:06
> *Para:* gvsig_internacional at listserv.gva.es
> *Asunto:* Re: [Gvsig_english] clean polygon? Issue with layers 
> importedfromOracle Spatial
>
>
> Dear list,
> in fact, exporting a shapefile to Oracle Spatial will result in change of
> the orientation of the vertices. When re-importing that Oracle spatial 
> layer
> to shapefile (export Oracle Spatial layer to shapefile), this "oracle
> spatial" orientation of vertices will remain! Is it a bug?
>
> Best,
> Wolfgang
>
> --
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> http://n2.nabble.com/clean-polygon-Issue-with-layers-imported-from-Oracle-Spatial-tp4585686p4586476.html
> Sent from the gvSIG international mailing list archive at Nabble.com.
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