NAME

       v.kcv  - Randomly partition points into test/train sets.

KEYWORDS

       vector, statistics

SYNOPSIS

       v.kcv
       v.kcv help
       v.kcv  [-dq]  input=name  output=name  k=integer column=string  [--overwrite]  [--verbose]
       [--quiet]

   Flags:
       -d
           Use drand48()

       -q
           Quiet

       --overwrite
           Allow output files to overwrite existing files

       --verbose
           Verbose module output

       --quiet
           Quiet module output

   Parameters:
       input=name
           Name of input vector map

       output=name
           Name for output vector map

       k=integer
           Number of partitions
           Options: 1-32767

       column=string
           Name for new column to which partition number is written
           Default: part

DESCRIPTION

       v.kcv  randomly  divides  a  points  lists  into  k sets of test/train  data  (for  k-fold
       cross  validation).   Test  partitions  are  mutually  exclusive.  That  is,  a point will
       appear in only one test partition and k-1 training  partitions.  The   program   generates
       a random point using the selected random number generator and then finds the closest point
       to it.  This site is removed from the candidate list (meaning that it will not be selected
       for  any  other test  set)  and saved  in the first test partition file.  This is repeated
       until enough points have been selected for the test partition.  The   number   of   points
       chosen  for  test partitions depends upon the number of sites available and the  number of
       partitions chosen (this number is made as consistent as possible while ensuring  that  all
       sites  will be chosen  for testing).  This  process of filling up a test partition is done
       k times.

NOTES

       An ideal random sites generator will follow a  Poisson  dis  only  be  as  random  as  the
       original  points.   This  program simply divides points up in a random manner.

       Be  warned  that  random number generation occurs over the intervals defined by the region
       of the map.

       This program may not work properly with Lat-long data.

SEE ALSO

       v.random and g.region

AUTHOR

       James Darrell McCauley ,
       when he was at: Agricultural Engineering Purdue University

       Update to 5.7 Radim Blazek 10 / 2004

       Last changed: $Date: 2011-11-08 01:42:51 -0800 (Tue, 08 Nov 2011) $

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