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 10:42:51 +0100 (Tue, 08 Nov 2011) $
Full index
© 2003-2011 GRASS Development Team
