[GRASS-user] confused by the GRASS Programmer's topology examples...

[G. Allegri]

Going on grasping the data structures...


>
>  - Point example: a point doesn't have nodes but have a line (P_LINE),
> with type GV_POINT.
> It's enough for me to get confused :)
> A P_LINE structure has a void * topo opaque element [2], which will point
> to the relative topology structure depending on the type. In case of a
> G_POINT type, what is the topology structure attached to the topo pointer?
>

Ok, as I supposed the topo pointer is NULL for points.


>
>  - Line example: two nodes with type GV_LINE. A P_NODE doesn't have a type
> [3], so how can it be... a GV_LINE? :(
>

Sorry, this is clear now. The type is referring to the lines attached to
the node.


>
> I'm missing something. Could you help to understand it?
> Thanks a lot,
> giovanni
>
>
> [1] http://grass.osgeo.org/programming7/vlibTopology.html#vlibTopoExamples
> [2] http://grass.osgeo.org/programming7/structP__line.html
> [3] http://grass.osgeo.org/programming7/structP__node.html
>
> --
> Giovanni Allegri
> http://about.me/giovanniallegri
> blog: http://blog.spaziogis.it
> GEO+ geomatica in Italia http://bit.ly/GEOplus
>



-- 
Giovanni Allegri
http://about.me/giovanniallegri
blog: http://blog.spaziogis.it
GEO+ geomatica in Italia http://bit.ly/GEOplus
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