NAME
s.qcount - indices for quadrat counts of sites lists
(GRASS Sites Program)
SYNOPSIS
s.qcount
s.qcount help
s.qcount [-ciq] input=name
n=value r=value
DESCRIPTION
s.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 sites falling within each quadrat are counted
and indices are calculated to estimate the departure of
site locations from complete spatial randomness.
OPTIONS
Flags:
- -c
- Print count data for each quadrat in the form of a sites list
(E|N|#n desc, where E is the easting and N is the northing of
the quadrat center, n is the quadrat number, and desc is an
integer indicating the number of sites contained within the quadrat).
- -i
- Suppress printing table of indices (default is to print indices
and not the count data).
- -q
- Quiet. Cut out the chatter.
Parameters:
- input=name
- Name of sites list defining qcount points.
- n=value
- Number of quadrats (integer).
- r=value
- Radius of quadrats (floating point).
NOTES
This program may not work properly with lat-long data. It uses
hypot()
in two files: count.c and findquads.c.
SEE ALSO
s.rand
Complete Spatial Randomness and Quadrat Methods -
GRASS Tutorial on s.qcount
(available as 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.
AUTHOR
James Darrell McCauley, Agricultural
Engineering, Purdue University,