NAME¶
v.db.univar - Calculates univariate statistics on selected table
column for a GRASS vector map.
KEYWORDS¶
vector, statistics
SYNOPSIS¶
v.db.univar
v.db.univar help
v.db.univar [-
e]
table=
string
column=
string [
database=
string]
[
driver=
string] [
where=
string] [--
verbose]
[--
quiet]
Flags:¶
- -e
-
Extended statistics (quartiles and 90th percentile)
- --verbose
-
Verbose module output
- --quiet
-
Quiet module output
Parameters:¶
- table=string
-
Name of data table
- column=string
-
Column on which to calculate statistics (must be numeric)
- database=string
-
Database/directory for table
- driver=string
-
Database driver
- where=string
-
WHERE conditions of SQL statement without 'where' keyword
DESCRIPTION¶
v.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 rast=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¶
r.univar, v.univar,, db.select,
d.vect.thematic
AUTHOR¶
Michael Barton, Arizona State University
and authors of
r.univar.sh
Last changed: $Date: 2011-09-04 15:23:30 +0200 (Sun, 04 Sep 2011) $
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