db.univar.1grass - Man Page

Calculates univariate statistics on selected table column.


database, statistics, attribute table


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]



Extended statistics (quartiles and 90th percentile)


Print stats in shell script style


Print usage summary


Verbose module output


Quiet module output


Force launching GUI dialog


table=name [required]

Name of attribute table

column=name [required]

Name of attribute column on which to calculate statistics (must be numeric)


Name of database


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


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


Percentile to calculate (requires extended statistics flag)
Options: 0-100
Default: 90


Output format
Options: plain, json, shell
plain: Plain text output
json: JSON (JavaScript Object Notation)
shell: Shell script style for Bash eval


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.


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


Michael Barton, Arizona State University

and authors of r.univar.sh

Source Code

Available at: db.univar source code (history)

Accessed: Wednesday Nov 15 17:41:20 2023

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