[GRASS-user] raster stats within vector

GRASS GRASS user
1

Dear all,

I have a raster map with continuous values, and need to extract some stats (like mean, std etc) assigning these “zonal” values as a vector column.
I just added the empty columns on the my vector map using :
v.db.addcol map=frag_ts columns=“FLOW_STD DOUBLE PRECISION”

How can I do this on grass?

cheers

milton

2

BTW,

my vector maps have polygons.

milton

2011/7/16 Milton Cezar Ribeiro <miltinho.astronauta@gmail.com>

Dear all,

I have a raster map with continuous values, and need to extract some stats (like mean, std etc) assigning these “zonal” values as a vector column.
I just added the empty columns on the my vector map using :
v.db.addcol map=frag_ts columns=“FLOW_STD DOUBLE PRECISION”

How can I do this on grass?

cheers

milton

3

v.rast.stats (menu: Vector-Update area attribute from raster) will calculate n, min, max, range, mean, stddev, variance, coeff_var, sum and optionally the 1st quartile, median, 3rd quartile, and given percentile. Columns will be created on the fly, you only have to give the ‘base name’ of the columns. I.e., no need to create a column yourself.

4

Hi Paulo,

Thanks a lot.

cheers

milton

2011/7/17 Paulo van Breugel <p.vanbreugel@gmail.com>

v.rast.stats (menu: Vector-Update area attribute from raster) will calculate n, min, max, range, mean, stddev, variance, coeff_var, sum and optionally the 1st quartile, median, 3rd quartile, and given percentile. Columns will be created on the fly, you only have to give the ‘base name’ of the columns. I.e., no need to create a column yourself.

On 07/16/2011 10:14 PM, Milton Cezar Ribeiro wrote:

BTW,

my vector maps have polygons.

milton

2011/7/16 Milton Cezar Ribeiro <miltinho.astronauta@gmail.com>

Dear all,

I have a raster map with continuous values, and need to extract some stats (like mean, std etc) assigning these “zonal” values as a vector column.
I just added the empty columns on the my vector map using :
v.db.addcol map=frag_ts columns=“FLOW_STD DOUBLE PRECISION”

How can I do this on grass?

cheers

milton


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