#### NAME
v.vect.stats - Count points in areas, calculate statistics.
#### KEYWORDS
vector, database, attribute table
#### SYNOPSIS
v.vect.stats
v.vect.stats help
v.vect.stats [-p] points=__name__ areas=__name__ [type=__string__[,__string__,...]]
[player=__integer__] [alayer=__integer__] [method=__string__] [pcolumn=__name__]
[ccolumn=__string__] [scolumn=__string__] [fs=__character|space|tab__]
[--verbose] [--quiet]
Flags:
-p
Print output to stdout, do not update attribute table
First column is always area category
--verbose
Verbose module output
--quiet
Quiet module output
Parameters:
points=__name__
Name of existing vector map with points
areas=__name__
Name of existing vector map with areas
type=__string[,string__,...]
Feature type
Feature type
Options: __point,centroid__
Default: __point__
player=__integer__
Layer number for points map
A single vector map can be connected to multiple database tables.
This number determines which table to use.
Default: __1__
alayer=__integer__
Layer number for area map
A single vector map can be connected to multiple database tables.
This number determines which table to use.
Default: __1__
method=__string__
Method for aggregate statistics
Options:
__sum,average,median,mode,minimum,min_cat,maximum,max_cat,range,stddev,variance,diversity__
pcolumn=__name__
Column name of points map to use for statistics
Column of points map must be numeric
ccolumn=__string__
Column name to upload points count
Column to hold points count, must be of type integer, will be
created if not existing
scolumn=__string__
Column name to upload statistics
Column to hold statistics, must be of type double, will be created
if not existing
fs=__character|space|tab__
Field separator
Output field separator
Default: __|__
#### DESCRIPTION
__v.vect.stats__ counts the number of points in vector map __points__ falling
into each area in vector map __areas__. Optionally statistics on point
attributes in __points__ are calculated for each area. The results are
either uploaded to the attribute table of the vector map __areas__ or
printed to stdout.
OPTIONS
__Statistical__ __Methods:__ Using numeric attribute values of all points
falling into a given area, a new value is detmined with the selected
method. __v.vect.stats__ can perform the following operations:
sum
The sum of values.
average
The average value of all point attributes (sum / count).
median
The value found half-way through a list of the attribute values,
when these are ranged in numerical order.
mode
The most frequently occurring value.
minimum
The minimum observed value.
min_cat
The point category corresponding to the minimum observed value.
maximum
The maximum observed value.
max_cat
The point category corresponding to the maximum observed value.
range
The range of the observed values.
stddev
The statistical standard deviation of the attribute values.
variance
The statistical variance of the attribute values.
diversity
The number of different attribute values.
#### NOTES
Points not falling into any area are ignored. Areas without category
(no centroid attached or centroid without category) are ignored. If no
points are falling into a given area, the point count is set to 0
(zero) and the statistics result to "null".
The columns __count_column__ and __stats_column__ are created if not existing.
If they do already exist, the __count_column__ must be of type integer and
the __stats_column__ of type double.
#### SEE ALSO
__v.distance,__ __r.distance,__ __v.what.vect__
#### AUTHOR
Markus Metz
__Last__ __changed:__ __$Date:__ __2008-08-13__ __21:52:37__ __+0200__ __(Wed,__ __13__ __Aug__ __2008)__ __$__
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