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) $

       Full index

       © 2003-2013 GRASS Development Team

GRASS 6.4.3                                                                                        v.kcv(1grass)