
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] 
Flags:
- -d
- Use drand48()
- -q
- Quiet
- --overwrite
- Force overwrite of output files
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
<darrell@mccauley-usa.com>,
when he was at: 
Agricultural
Engineering
Purdue University
Update to 5.7 Radim Blazek 10 / 2004
Last changed: $Date: 2006/01/02 14:44:51 $
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