[GRASS-user] Point attributes to a polygons

Micha Silver micha at arava.co.il
Thu Jun 25 09:44:38 EDT 2009

Micha Silver wrote:

> xavier garcia acosta wrote:
>> Yes, you have understood my question. I've tried that you have 
>> recommended to my and now I have the next problem, I've tried to do 
>> “v.patch” with the option “copy also attribute table” with my two 
>> GRASS vector maps and I have the error “Number of columns differ”. Do 
>> you know how can I solve this?
> Yes you're right.
> To get this correct you have to add an (empty) attribute table with 
> exactly the same columns to the boundary vector first. So:
> db.describe <your_point_vector> (to get the exact column types)
> v.db.addtable <your_line_vector> column="col1 datatype, col2 datatype, 
> ..."
> then you succeed with:
> v.patch -e <your_point_Vector>,<your_line_vector> out=tmp_patch
> v.type tmp_patch out=point_line_vector
> The output to v.type should show that you have boundaries and 
> centroids. Check attributes with
> v.db.select <your_line_vector>
Ooops, typo, sorry.
That last line should be
v.db.select <point_line_vector>

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