GRASS logo

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,...]] [format=string] [--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
format=string
Output format
Options: plain, json, shell
plain: Plain text output
json: JSON (JavaScript Object Notation)
shell: Shell script style for Bash eval

Table of contents

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

AUTHORS

Michael Barton, Arizona State University

and authors of r.univar.sh

SOURCE CODE

Available at: db.univar source code (history)

Latest change: Thursday Jun 09 12:03:16 2022 in commit: 120f198fca22a564334d7721fabbe8c6e299bf6b


Main index | Database index | Topics index | Keywords index | Graphical index | Full index

© 2003-2024 GRASS Development Team, GRASS GIS 8.3.3dev Reference Manual