NAME

       v.db.univar   -  Calculates  univariate  statistics  on  selected table column for a GRASS
       vector map.

KEYWORDS

       vector, statistics, attribute table

SYNOPSIS

       v.db.univar
       v.db.univar --help
       v.db.univar    [-eg]    map=name     [layer=string]     column=name      [where=sql_query]
       [percentile=float[,float,...]]   [--help]  [--verbose]  [--quiet]  [--ui]

   Flags:
       -e
           Extended statistics (quartiles and 90th percentile)

       -g
           Print stats in shell script style

       --help
           Print usage summary

       --verbose
           Verbose module output

       --quiet
           Quiet module output

       --ui
           Force launching GUI dialog

   Parameters:
       map=name [required]
           Name of vector map
           Or data source for direct OGR access

       layer=string
           Layer number or name
           Vector  features  can have category values in different layers. This number determines
           which layer to use. When used with direct OGR access this is the layer name.
           Default: 1

       column=name [required]
           Name of attribute column on which to calculate statistics (must be numeric)

       where=sql_query
           WHERE conditions of SQL statement without ’where’ keyword
           Example: income < 1000 and inhab >= 10000

       percentile=float[,float,...]
           Percentile to calculate (requires extended statistics flag)
           Options: 0-100
           Default: 90

DESCRIPTION

       v.db.univar calculates basic univariate statistics for  numeric  attributes  in  a  vector
       attribute  table.  It  will  calculate  minimum, maximum, range, mean, standard deviation,
       variance, coefficient of variation, quartiles,  median,  and  90th  percentile.   It  uses
       db.select to create list values for statistical calculations.  NOTES A database connection
       must be defined for the selected vector layer.

EXAMPLE

       In this example, random points are sampled from the elevation map (North  Carolina  sample
       dataset) and univariate statistics performed:
       g.region raster=elevation -p
       v.random output=samples n=100
       v.db.addtable samples column="heights double precision"
       v.what.rast samples raster=elevation colum=heights
       v.db.select samples
       v.db.univar samples colum=heights

SEE ALSO

        db.univar, r.univar, v.univar, db.select, d.vect.thematic

AUTHOR

       Michael Barton, Arizona State University

       and authors of r.univar.sh

       Last changed: $Date: 2014-12-19 22:55:37 +0100 (Fri, 19 Dec 2014) $

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