[GRASS-user] Some questions

[Martin Besta]

Hi all,
I have two questions and maybe one solution.

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.

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

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.

Thx for your help.
Martin

 
> On 5/30/07, *Martin Besta* <martin.besta at googlemail.com 
> <mailto:martin.besta at googlemail.com>> wrote:
>
>     Hi all,
>     I am new here and to grass, so I have some questions about working
>     with grass.
>
>
>
> Hello and welcome to the fun world of open source GRASS GIS!!!
>
>     First,
>     I have some maps and one line, witch represents the boundary of
>     area. And I need to trim my maps with this line (somethings like
>     Clip by ESRI). Is it possible with Grass tools? 
>
>
> v.overlay will do a clip, inputting a line and a area as the 
> "clipper".  by selecting the "and" operator you will get the clipped 
> lines.
>  
>
>     Next...
>     To my polygon map I want to add some polygons from other polygon
>     map (Update, again like ESRI). I am not sure if v.patch is the
>     best solution to get this
>
>
> v.patch should do the trick.
>  
>
>     Next..
>     Can I edit the column header (name and type) of attribute table? I
>     know another WIN software that can it do, but i am interested in
>     GRASS now. Is it possible to remove some columns from the table
>     with Grass? 
>
>
> v.category looks like it edits attributes.
>  
> Sorry I cant be more definitive, but I'm working off of the old memory 
> banks.  =D
>
>
>     I would be happy if you could me give any answers.
>     Best regards
>     _______________________________________________
>     grassuser mailing list
>     grassuser at grass.itc.it <mailto:grassuser at grass.itc.it>
>     http://grass.itc.it/mailman/listinfo/grassuser
>
>