NAME

       v.qcount  - Indices for quadrat counts of sites lists.

KEYWORDS

       vector, statistics

SYNOPSIS

       v.qcount
       v.qcount help
       v.qcount [-gq] input=string  [output=string]  n=integer r=float  [--overwrite]  [--verbose]  [--quiet]

   Flags:
       -g
           Print results in shell script style

       -q
           Quiet

       --overwrite
           Allow output files to overwrite existing files

       --verbose
           Verbose module output

       --quiet
           Quiet module output

   Parameters:
       input=string
           Vector of points defining sample points

       output=string
           Output quadrant centres, number of points is written as category

       n=integer
           Number of quadrats

       r=float
           Quadrat radius

DESCRIPTION

       v.qcount  chooses  n circular quadrats of radius r such that they are completely within the bounds of the
       current region and no two quadrats overlap.  The number of points falling within each quadrat are counted
       and indices are calculated to estimate the departure of point locations from complete spatial randomness.

NOTES

       This program may not work properly with lat-long  data.  It  uses  hypot()  in  two  files:  count.c  and
       findquads.c.

SEE ALSO

       v.random

       Complete  Spatial  Randomness  and Quadrat Methods  - GRASS Tutorial on v.qcount (only available as older
       file s.qcount-tutorial.ps),

       General references include:
       Noel A. C. Cressie.   Statistics  for  Spatial  Data.   Wiley  Series  in  Probability  and  Mathematical
       Statistics. John Wiley & Sons, New York, NY, 1st edition, 1991.
       Brian D. Ripley.  Spatial Statistics. John Wiley \& Sons, New York, NY, 1981.

       References to the indices include:
       F.  N. David and P. G. Moore.  Notes on contagious distributions in plant populations.  Annals of Botany,
       18:47-53, 1954.
       J. B. Douglas.  Clustering and aggregation.  Sankhya B, 37:398-417, 1975.
       R. A. Fisher, H. G. Thornton, and W. A. Mackenzie.  The accuracy of the plating method of estimating  the
       density of bacterial populations.  Annals of Applied Biology, 9:325-359, 1922.
       M. Lloyd. Mean crowding.  Journal of Animal Ecology, 36:1-30, 1967.
       M.  Morista.  Measuring the dispersion and analysis of distribution patterns.  Memoires of the Faculty of
       Science, Kyushu University, Series E.  Biology, 2:215-235, 1959.

BUGS

       Timestamp not working for header part of counts output. (2000-10-28)

       Please send all bug fixes and comments to the author or the grass development team.
       http://grass.osgeo.org.

AUTHORS

       James Darrell McCauley ,
       when he was at: Agricultural Engineering Purdue University

       Modified for GRASS 5.0 by Eric G. Miller (2000-10-28)
       Modified for GRASS 5.7 by R. Blazek (2004-10-14)

       Last changed: $Date: 2011-11-08 01:42:51 -0800 (Tue, 08 Nov 2011) $

       Full index

       © 2003-2013 GRASS Development Team

GRASS 6.4.3                                                                                     v.qcount(1grass)