.TH v.vect.stats 1grass "" "GRASS 6.4.4" "Grass User's Manual"
.SH NAME
\fI\fBv.vect.stats\fR\fR  - Count points in areas, calculate statistics.
.SH KEYWORDS
vector, database, attribute table
.SH SYNOPSIS
\fBv.vect.stats\fR
.br
\fBv.vect.stats help\fR
.br
\fBv.vect.stats\fR [\-\fBp\fR] \fBpoints\fR=\fIname\fR \fBareas\fR=\fIname\fR  [\fBtype\fR=\fIstring\fR[,\fIstring\fR,...]]   [\fBplayer\fR=\fIinteger\fR]   [\fBalayer\fR=\fIinteger\fR]   [\fBmethod\fR=\fIstring\fR]   [\fBpcolumn\fR=\fIname\fR]   [\fBccolumn\fR=\fIstring\fR]   [\fBscolumn\fR=\fIstring\fR]   [\fBfs\fR=\fIcharacter|space|tab\fR]   [\-\-\fBverbose\fR]  [\-\-\fBquiet\fR] 
.SS Flags:
.IP "\fB\-p\fR" 4m
.br
Print output to stdout, do not update attribute table
.br
First column is always area category
.IP "\fB\-\-verbose\fR" 4m
.br
Verbose module output
.IP "\fB\-\-quiet\fR" 4m
.br
Quiet module output
.PP
.SS Parameters:
.IP "\fBpoints\fR=\fIname\fR" 4m
.br
Name of existing vector map with points
.IP "\fBareas\fR=\fIname\fR" 4m
.br
Name of existing vector map with areas
.IP "\fBtype\fR=\fIstring[,\fIstring\fR,...]\fR" 4m
.br
Feature type
.br
Feature type
.br
Options: \fIpoint,centroid\fR
.br
Default: \fIpoint\fR
.IP "\fBplayer\fR=\fIinteger\fR" 4m
.br
Layer number for points map
.br
A single vector map can be connected to multiple database tables. This number determines which table to use.
.br
Default: \fI1\fR
.IP "\fBalayer\fR=\fIinteger\fR" 4m
.br
Layer number for area map
.br
A single vector map can be connected to multiple database tables. This number determines which table to use.
.br
Default: \fI1\fR
.IP "\fBmethod\fR=\fIstring\fR" 4m
.br
Method for aggregate statistics
.br
Options: \fIsum,average,median,mode,minimum,min_cat,maximum,max_cat,range,stddev,variance,diversity\fR
.IP "\fBpcolumn\fR=\fIname\fR" 4m
.br
Column name of points map to use for statistics
.br
Column of points map must be numeric
.IP "\fBccolumn\fR=\fIstring\fR" 4m
.br
Column name to upload points count
.br
Column to hold points count, must be of type integer, will be created if not existing
.IP "\fBscolumn\fR=\fIstring\fR" 4m
.br
Column name to upload statistics
.br
Column to hold statistics, must be of type double, will be created if not existing
.IP "\fBfs\fR=\fIcharacter|space|tab\fR" 4m
.br
Field separator
.br
Output field separator
.br
Default: \fI|\fR
.PP
.SH DESCRIPTION
\fIv.vect.stats\fR counts the number of points in vector map
\fIpoints\fR falling into each area in vector map \fIareas\fR.
Optionally statistics on point attributes in \fIpoints\fR are
calculated for each area. The results are either uploaded to the
attribute table of the vector map \fIareas\fR or printed to stdout.
.SS OPTIONS
\fIStatistical Methods:\fR
Using numeric attribute values of all points falling into a given area,
a new value is detmined with the selected method.
\fIv.vect.stats\fR can perform the following operations:
.PP
.IP "\fBsum\fR 
.br
The sum of values.
.IP "\fBaverage\fR 
.br
The average value of all point attributes (sum / count).
.IP "\fBmedian\fR 
.br
The value found half-way through a list of the
attribute values, when these are ranged in numerical order.
.IP "\fBmode\fR 
.br
The most frequently occurring value.
.IP "\fBminimum\fR 
.br
The minimum observed value.
.IP "\fBmin_cat\fR 
.br
The point category corresponding to the minimum observed value.
.IP "\fBmaximum\fR 
.br
The maximum observed value.
.IP "\fBmax_cat\fR 
.br
The point category corresponding to the maximum observed value.
.IP "\fBrange\fR 
.br
The range of the observed values.
.IP "\fBstddev\fR 
.br
The statistical standard deviation of the attribute values.
.IP "\fBvariance\fR 
.br
The statistical variance of the attribute values.
.IP "\fBdiversity\fR 
.br
The number of different attribute values.
.PP
.SH 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".
.PP
The columns \fIcount_column\fR and \fIstats_column\fR are created if not
existing. If they do already exist, the \fIcount_column\fR must be of
type integer and the \fIstats_column\fR of type double.
.SH SEE ALSO
\fI
v.distance,
r.distance,
v.what.vect
\fR
.SH AUTHOR
Markus Metz
.PP
\fILast changed: $Date: 2008-08-13 21:52:37 +0200 (Wed, 13 Aug 2008) $\fR
.PP
Full index
.PP
© 2003-2014 GRASS Development Team