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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