db.univar(1)

NAME
db.univar - Calculates univariate statistics on selected table column.

KEYWORDS
database, statistics, attribute table

SYNOPSIS
db.univar
db.univar --help
db.univar [-eg] table=name column=name [database=name] [driver=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:

table=name [required]
    Name of attribute table

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

database=name
    Name of database

driver=name
    Name of database driver
    Options: dbf, odbc, ogr, sqlite, pg

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

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

DESCRIPTION
db.univar calculates basic univariate statistics for numeric attributes in a data 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 If the database and driver are not specified, the default values set in db.connect will be used.

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 column=heights
v.db.select samples
db.univar samples column=heights

SEE ALSO
v.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: $Date$

SOURCE CODE

Available at: db.univar source code (history)

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