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NAME

v.univar - Calculates univariate statistics for attribute. Variance and standard deviation is calculated only for points if specified.

KEYWORDS

vector, statistics

SYNOPSIS

v.univar
v.univar help
v.univar [-ged] map=name [layer=integer] [type=string[,string,...]] [column=string] [where=sql_query] [percentile=integer] [--verbose] [--quiet]

Flags:

-g
Print the stats in shell script style
-e
Calculate extended statistics
-d
Calculate geometry distances instead of table data
--verbose
Verbose module output
--quiet
Quiet module output

Parameters:

map=name
Name of input vector map
layer=integer
Layer number
A single vector map can be connected to multiple database tables. This number determines which table to use.
Default: 1
type=string[,string,...]
Feature type
Options: point,line,boundary,centroid,area
Default: point,line,area
column=string
Column name
where=sql_query
WHERE conditions of SQL statement without 'where' keyword
Example: income < 1000 and inhab >= 10000
percentile=integer
Percentile to calculate (requires extended statistics flag)
Options: 0-100
Default: 90

DESCRIPTION

v.univar calculates univariate statistics of vector map features. This includes the number of features counted, minimum and maximum values, and range. Variance and standard deviation is calculated only for points if type=point is defined.

Extended statistics adds median, 1st and 3rd quartiles, and 90th percentile.

EXAMPLE

g.region rast=elevation.10m -p
v.random out=samples n=100
v.db.addtable samples col="heights double precision"
v.what.rast samples rast=elevation.10m col=heights
v.db.select samples

v.univar samples col=heights type=point

SEE ALSO

v.neighbors

AUTHOR

Radim Blazek, ITC-irst

Last changed: $Date: 2011-11-08 01:42:51 -0800 (Tue, 08 Nov 2011) $


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