v.random.strat.sampling - GRASS GIS manual

NAME

v.random.strat.sampling - sample data

KEYWORDS

vector, sampling, statistics, random, point pattern, stratified random sampling

SYNOPSIS

v.random.strat.sampling

v.random.strat.sampling --help

v.random.strat.sampling input=name [column=name] output=name npoints=integer [intcolumn=name] [--overwrite] [--help] [--verbose] [--quiet] [--ui]

Flags:

--overwrite: Allow output files to overwrite existing files
--help: Print usage summary
--verbose: Verbose module output
--quiet: Quiet module output
--ui: Force launching GUI dialog

Parameters:

input=name [required]: Name of input vector map; Or data source for direct OGR access
column=name: Name of column with class information
output=name [required]: Name for output vector map
npoints=integer [required]: Number of points to be created for each class; Default: 100
intcolumn=name: Name of column to create new integer class information

DESCRIPTION
EXAMPLE
SEE ALSO
AUTHORS

DESCRIPTION

v.random.strat.sampling allows to sample training data in a stratified way. The number of points is the amount of vector sample points to be created for each class.

The module can deal with both numeric and text columns.

EXAMPLE

In this example we sample points from the North Carolina (USA) urban area map (from North Carolina sample dataset):

g.region vector=urbanarea -p

# show different attributes
v.db.select urbanarea_sampled_strat column=UA_TYPE -c | sort -u
UA
UC

# sample points randomly but stratified by the two classes from the vector areas
v.random.strat.sampling input=urbanarea column=UA_TYPE output=urbanarea_sampled_strat npoints=50

# new point map: show the attributes of the 50 UA  + 50 UC points
v.db.select urbanarea_sampled_strat

v.info -t urbanarea_sampled_strat
nodes=0
points=100
lines=0
boundaries=0
centroids=0
areas=0
islands=0
primitives=100
map3d=0