v.kernel(1)

1v.kernel(1)                   Grass User's Manual                  v.kernel(1)
2
3
4

NAME

6       v.kernel   -  Generates  a  raster  density map from vector points data
7       using a moving 2D isotropic Gaussian kernel or optionally  generates  a
8       vector density map on vector network with a 1D kernel.
9

KEYWORDS

11       vector, kernel density
12

SYNOPSIS

14       v.kernel
15       v.kernel help
16       v.kernel  [-oqv] input=name  [net=name]  output=name stddeviation=float
17       [dsize=float]     [segmax=float]      [distmax=float]      [mult=float]
18       [--verbose]  [--quiet]
19
20   Flags:
21       -o
22           Try  to calculate an optimal standard deviation with 'stddeviation'
23           taken as maximum (experimental)
24
25       -q
26           Only calculate optimal standard deviation and exit (no map is writ‐
27           ten)
28
29       -v
30           Run verbosely
31
32       --verbose
33           Verbose module output
34
35       --quiet
36           Quiet module output
37
38   Parameters:
39       input=name
40           Input vector with training points
41
42       net=name
43           Input network vector map
44
45       output=name
46           Output raster/vector map
47
48       stddeviation=float
49           Standard deviation in map units
50
51       dsize=float
52           Discretization error in map units
53           Default: 0.
54
55       segmax=float
56           Maximum length of segment on network
57           Default: 100.
58
59       distmax=float
60           Maximum distance from point to network
61           Default: 100.
62
63       mult=float
64           Multiply the density result by this number
65           Default: 1.
66

DESCRIPTION

68       Generates  a  raster density map from vector points data using a moving
69       2D isotropic Gaussian kernel or optionally generates a  vector  density
70       map on vector network with a 1D kernel.
71

NOTES

73       The mult option is needed to overcome the limitation that the resulting
74       density in case of a vector map output is stored as category (Integer).
75       The density result stored as category may be multiplied by this number.
76
77       With the -o flag (experimental) the command tries to calculate an opti‐
78       mal standard deviation. The value of stddeviation is taken  as  maximum
79       value.  Standard  deviation  is  calculated  using ALL points, not just
80       those in the current region.
81

LIMITATIONS

83       The modules only considers the presence of point,  but  not  (yet)  any
84       attribute values.
85

AUTHOR

90       Stefano Menegon, ITC-irst, Trento, Italy
91       Radim Blazek (network part)
92
93       Last changed: $Date: 2005-01-11 11:23:39 +0100 (Tue, 11 Jan 2005) $
94
95       Full index
96
97       © 2003-2008 GRASS Development Team
98
99
100
101GRASS 6.3.0                                                        v.kernel(1)