v.qcount(1)

1v.qcount(1)                   Grass User's Manual                  v.qcount(1)
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NAME

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

9       vector, statistics
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SYNOPSIS

12       v.qcount
13       v.qcount help
14       v.qcount   [-gq]   input=string    [output=string]   n=integer  r=float
15       [--overwrite]  [--verbose]  [--quiet]
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17   Flags:
18       -g
19           Print results in shell script style
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21       -q
22           Quiet
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24       --overwrite
25           Allow output files to overwrite existing files
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27       --verbose
28           Verbose module output
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30       --quiet
31           Quiet module output
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33   Parameters:
34       input=string
35           Vector of points defining sample points
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37       output=string
38           Output quadrant centres, number of points is written as category
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40       n=integer
41           Number of quadrats
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43       r=float
44           Quadrat radius
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DESCRIPTION

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

54       This program may not work properly with lat-long data. It uses  hypot()
55       in two files: count.c and findquads.c.
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58       v.random
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60       Complete  Spatial  Randomness  and Quadrat Methods  - GRASS Tutorial on
61       v.qcount (only available as older file s.qcount-tutorial.ps),
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63       General references include:
64       Noel A. C. Cressie.  Statistics for  Spatial  Data.   Wiley  Series  in
65       Probability  and  Mathematical Statistics. John Wiley & Sons, New York,
66       NY, 1st edition, 1991.
67       Brian D. Ripley.  Spatial Statistics.  John Wiley \&  Sons,  New  York,
68       NY, 1981.
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70       References to the indices include:
71       F.  N.  David  and  P.  G. Moore.  Notes on contagious distributions in
72       plant populations.  Annals of Botany, 18:47-53, 1954.
73       J. B. Douglas.  Clustering and  aggregation.   Sankhya  B,  37:398-417,
74       1975.
75       R. A. Fisher, H. G. Thornton, and W. A. Mackenzie.  The accuracy of the
76       plating method of estimating  the  density  of  bacterial  populations.
77       Annals of Applied Biology, 9:325-359, 1922.
78       M. Lloyd.  Mean crowding.  Journal of Animal Ecology, 36:1-30, 1967.
79       M. Morista.  Measuring the dispersion and analysis of distribution pat‐
80       terns.  Memoires of the Faculty of Science, Kyushu  University,  Series
81       E.  Biology, 2:215-235, 1959.
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BUGS

84       Timestamp not working for header part of counts output. (2000-10-28)
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86       Please  send  all  bug  fixes  and  comments to the author or the grass
87       development team.
88       http://grass.itc.it.
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AUTHOR

91       James Darrell McCauley ,
92       when he was at: Agricultural Engineering Purdue University
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94       Modified for GRASS 5.0 by Eric G. Miller (2000-10-28)
95       Modified for GRASS 5.7 by R. Blazek (2004-10-14)
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97       Last changed: $Date: 2004-12-06 11:45:44 +0100 (Mon, 06 Dec 2004) $
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99       Full index
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101       © 2003-2008 GRASS Development Team
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105GRASS 6.3.0                                                        v.qcount(1)