[GRASS-user] Resetting vector cats and/or a quick exchange between numpy and vector tables

Michel Wortmann wortmann at pik-potsdam.de
Fri Feb 21 06:06:21 PST 2014

Hi list,
I have some (basic) vector related questions:

After cleaning a vector map, it doesnt have continuous (i.e. no gaps in 
numbering) categories, how do I efficiently reset these to so that they 
have regular increments (i.e. 1) again? r.clump does something very 
similar with vectors. I have tried dropping and adding a new table, 
deleting and adding categories with v.category. I thought v.reclass may 
do the trick but I'd first need a column with continuous numbers for that.

Somewhat related to this, what is the best/most efficient way of 
updating an entire column of a vector table from a numpy array. v.update 
does do it for one entry only, i.e. looping would be possible, but that 
takes ages. Would I have to go back to using basic sqlite3 packages for 


Michel Wortmann | MPhil/PhD student (University College London) | RD II: 
Impacts & Vulnerabilities | PIK | wortmann at pik-potsdam.de | +49 331 288-2461
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