[GRASS-user] RE : RE : Merge polygone with same attribut of a shapefile

[Nikos Alexandris]

BLANDENIER Lucien wrote:

> Ok, but I will obtain statistics for each polygons separately and not a
> "global" statistic considering all the polygons of a same category?

If I understand your aim, I think you can have your Polygons map and attach to 
it 2 layers.

The 1st layer would contain 1 category value for all features of your 
interest, e.g. areas (each defined as a "boundary + centroid"). Then, 
"v.rast.stats" will operate on the category/-ies values for all/-multiple 
areas queried.

In the 2nd layer, you can define a unique category for each vector feature. 
So, the stats should be single-vector-feature oriented.

Funny, I am "stuck" as on how to (re-)define in layer 2 the "cat" column with 
unique categories for each (internal) feature id.  There is nothing that 
helps-out towards this (simple?) task in the manuals (v.to.db).

Any help?

Nikos

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