xenial (1) v.db.univar.1grass.gz

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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       © 2003-2016 GRASS Development Team, GRASS GIS 7.0.3 Reference Manual