Provided by: grass-doc_6.4.3-3_all
v.vect.stats - Count points in areas, calculate statistics.
vector, database, attribute table
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: |
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.
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.
v.distance, r.distance, v.what.vect
Markus Metz Last changed: $Date: 2008-08-13 21:52:37 +0200 (Wed, 13 Aug 2008) $ Full index © 2003-2013 GRASS Development Team