[GRASS-user] Some questions

[Hamish]

Martin Besta wrote:
> 
> When I am executing v.overlay (to clip my map with boundary line) I 
> recieve always the clipped line (ainput is line, binput is area), 
> however I need the polygon. When I switched first and second input 
> layer, I had recieved an empty layer.

note features to be considered should have some cat value. (v.category)

> A little problem I have with v.buffer...the output is without attribut
> table.

v.buffer can't transfer the attribute as a new area may be from the
overlap of two original areas with different attributes. (this was
buried in the help page, I've just made it more visible)


> I was trying first v.buffer, then v.db.addtable and finaly v.overaly
> intersect with input line for buffer. But then is the output line
> again.

can you reproduce the effect using the demo spearfish dataset, and post
the command line commands?
 
> The problem with the spatial dissolve I did with the conversion to 
> raster and raster to vector again. Every raster cell has value from
> the attribut (biotop code in my layer) and the conversion to vector
> again dissolved all other lines, only polygons boundaries stay on.

glad you found something that worked; it would be nicer to not need the
conversion from v->r->v of course.

v.distance might help for reconnecting attributes.


Hamish