This is the command v.db.univargrass that can be run in the OnWorks free hosting provider using one of our multiple free online workstations such as Ubuntu Online, Fedora Online, Windows online emulator or MAC OS online emulator
PROGRAM:
NAME
v.db.univar - Calculates univariate statistics on selected table column for a GRASS
vector map.
KEYWORDS
vector, statistics, attribute table
SYNOPSIS
v.db.univar
v.db.univar --help
v.db.univar [-eg] map=name [layer=string] column=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:
map=name [required]
Name of vector map
Or data source for direct OGR access
layer=string
Layer number or name
Vector features can have category values in different layers. This number determines
which layer to use. When used with direct OGR access this is the layer name.
Default: 1
column=name [required]
Name of attribute column on which to calculate statistics (must be numeric)
where=sql_query
WHERE conditions of SQL statement without ’where’ keyword
Example: income < 1000 and inhab >= 10000
percentile=float[,float,...]
Percentile to calculate (requires extended statistics flag)
Options: 0-100
Default: 90
DESCRIPTION
v.db.univar calculates basic univariate statistics for numeric attributes in a vector
attribute 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 A database connection
must be defined for the selected vector layer.
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 colum=heights
v.db.select samples
v.db.univar samples colum=heights
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