GRASS logo

NAME

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

KEYWORDS

vector, kernel density

SYNOPSIS

v.kernel
v.kernel help
v.kernel [-oqv] input=name [net=name] output=name stddeviation=float [dsize=float] [segmax=float] [distmax=float] [mult=float] [--verbose] [--quiet]

Flags:

-o
Try to calculate an optimal standard deviation with 'stddeviation' taken as maximum (experimental)
-q
Only calculate optimal standard deviation and exit (no map is written)
-v
Run verbosely
--verbose
Verbose module output
--quiet
Quiet module output

Parameters:

input=name
Input vector with training points
net=name
Input network vector map
output=name
Output raster/vector map
stddeviation=float
Standard deviation in map units
dsize=float
Discretization error in map units
Default: 0.
segmax=float
Maximum length of segment on network
Default: 100.
distmax=float
Maximum distance from point to network
Default: 100.
mult=float
Multiply the density result by this number
Default: 1.

DESCRIPTION

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

NOTES

The mult option is needed to overcome the limitation that the resulting density in case of a vector map output is stored as category (Integer). The density result stored as category may be multiplied by this number.

With the -o flag (experimental) the command tries to calculate an optimal standard deviation. The value of stddeviation is taken as maximum value. Standard deviation is calculated using ALL points, not just those in the current region.

LIMITATIONS

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

SEE ALSO

v.surf.rst

AUTHOR

Stefano Menegon, ITC-irst, Trento, Italy
Radim Blazek (network part)

Last changed: $Date: 2005-01-11 02:23:39 -0800 (Tue, 11 Jan 2005) $


Main index - vector index - Full index

© 2003-2008 GRASS Development Team