NAME
i.shape - Performs spatial shape identification and classification on a raster map
(GRASS Image Processing Program)
SYNOPSIS
i.shape
i.shape help
i.shape input=name
output=name
[width=value]
[threshold=value]
[orientations=value]
DESCRIPTION
Reads a GRASS raster map as input. Calculates spatial shape identification
and classification on a raster map. Be sure to carefully set your
resolution (using
g.region)
before running this program, or else your computer could
run out of memory.
OPTIONS
Parameter:
- input=name
- Name of input raster map layer.
- output=name
- Fourier transformation output file
- width=value
- This parameter determines the x-y extent of the
Gaussian filter. The default value is 9; higher and lower
values can be tested by the user. Increasing the width
will result in finding "edges" representing more gradual
changes in cell values.
Default: 9
- threshold=value
- This parameter determines the "sensitivity" of the
Gaussian filter. The default value is 10; higher and
lower values can be tested by the user. Increasing the
threshold value will result in fewer edges being found.
Default: 10
- orientations=value
- This value is the number of azimuth directions the
cells on the output raster map layer are categorized into
(similar to the aspect raster map layer produced by the
r.slope.aspect
program). For example, a value of 16 would result in
detected edges being categorized into one of 16 bins
depending on the direction of the edge at that point.
Default: 1
The current region definition and mask settings are respected
when reading the input map.
NOTES
[..]
SEE ALSO
i.fft
i.ifft
r.mapcalc
g.region
i.texture
i.zc
AUTHOR
Hong Chun Zhuang
Sep.21,1992 at EC, CERL
Last changed: $Date$