NAME

       r.surf.fractal  - Creates a fractal surface of a given fractal dimension.

KEYWORDS

       raster, surface, fractal

SYNOPSIS

       r.surf.fractal
       r.surf.fractal --help
       r.surf.fractal output=name  [dimension=float]   [number=integer]   [--overwrite]  [--help]
       [--verbose]  [--quiet]  [--ui]

   Flags:
       --overwrite
           Allow output files to overwrite existing files

       --help
           Print usage summary

       --verbose
           Verbose module output

       --quiet
           Quiet module output

       --ui
           Force launching GUI dialog

   Parameters:
       output=name [required]
           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).

       This module generates naturally looking synthetical elevation models (DEM).

NOTE

       This module requires the FFTW library for computing Discrete Fourier Transforms.

EXAMPLE

       Generate surface using fractals in selected region,  set  color  table  and  display  with
       shade.
       g.region -p raster=elevation
       r.surf.fractal output=fractals
       r.colors map=fractals color=byr
       r.relief input=fractals output=fractals_shade
       d.mon wx0
       d.shade shade=fractals_shade color=fractals b=50
       Artificial surface created with fractals
       Compare results when using different fractal dimensions:
       # 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
       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)

REFERENCES

       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, v.surf.idw, v.surf.rst

AUTHOR

       Jo Wood, Midlands Regional Research Laboratory (ASSIST), University of Leicester

       Last changed: $Date: 2015-07-20 10:49:51 +0200 (Mon, 20 Jul 2015) $

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