NAME¶
r.surf.fractal - Creates a fractal surface of a given fractal
dimension.
KEYWORDS¶
raster
SYNOPSIS¶
r.surf.fractal
r.surf.fractal help
r.surf.fractal output=
string [
dimension=
float]
[
number=
integer] [--
verbose] [--
quiet]
Parameters:¶
- output=string
-
Name for output raster map
- dimension=float
-
Fractal dimension of surface (2 < D < 3)
Default: 2.05
- number=integer
-
Number of intermediate images to produce
Default: 0
DESCRIPTION¶
r.surf.fractal creates a fractal surface of a given fractal dimension. It
uses the spectral synthesis method. The module can create intermediate layers
showing the build up of different spectral coefficients (see Saupe, pp.106-107
for an example of this).
Use this module to generate naturally looking synthetical elevation models
(DEM).
NOTE¶
This module requires the FFTW library for computing Discrete Fourier Transforms.
EXAMPLE¶
# D=2.0005
g.region -dp
r.surf.fractal out=dem_d2_0005 dim=2.0005
r.info -r dem_d2_0005
r.mapcalc "dem_d2_0005_final = 1.0 * dem_d2_0005 +
abs(min(dem_d2_0005))"
r.colors dem_d2_0005_final color=terrain
r.slope.aspect dem_d2_0005_final aspect=dem_d2_0005_final_as
# D=2.90
r.surf.fractal out=dem_d2_90 dim=2.90
r.info -r dem_d2_90
r.mapcalc "dem_d2_90_final = 1.0 * dem_d2_90 + abs(min(dem_d2_90))"
r.colors dem_d2_90_final color=terrain
r.slope.aspect dem_d2_90_final aspect=dem_d2_90_final_as
d.mon x0
d.erase -f
d.split.frame
d.frame -s uno
d.rast dem_d2_0005_final
d.frame -s dos
d.rast dem_d2_0005_final_as
d.frame -s tres
d.rast dem_d2_90_final
d.frame -s cuatro
d.rast dem_d2_90_final_as
Artificial DEMs created with fractals:
top: fractal dimension d=2.0005 (left: elevation map, right: aspect map)
top: fractal dimension d=2.90 (left: elevation map, right: aspect map)
REFERENCE¶
Saupe, D. (1988) Algorithms for random fractals, in Barnsley M., Devaney R.,
Mandelbrot B., Peitgen, H-O., Saupe D., and Voss R. (1988) The Science of
Fractal Images, Ch. 2, pp.71-136. London: Springer-Verlag.
SEE ALSO¶
r.surf.contour,
r.surf.idw,
r.surf.gauss,
r.surf.random,
r.surf.idw2,
v.surf.idw,
v.surf.rst
AUTHOR¶
Jo Wood, Midlands Regional Research Laboratory (ASSIST), University of Leicester
Last changed: $Date: 2012-11-27 01:18:53 +0100 (Tue, 27 Nov 2012) $
Full index
© 2003-2014 GRASS Development Team
