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) $

       Full index

       © 2003-2013 GRASS Development Team

GRASS 6.4.3                                                                                 v.vect.stats(1grass)