r.surf.fractal(1grass)

1r.surf.fractal(1)           GRASS GIS User's Manual          r.surf.fractal(1)
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NAME

6       r.surf.fractal   -  Creates a fractal surface of a given fractal dimen‐
7       sion.
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KEYWORDS

10       raster, surface, fractal
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SYNOPSIS

13       r.surf.fractal
14       r.surf.fractal --help
15       r.surf.fractal   output=name    [dimension=float]      [number=integer]
16       [--overwrite]  [--help]  [--verbose]  [--quiet]  [--ui]
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18   Flags:
19       --overwrite
20           Allow output files to overwrite existing files
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22       --help
23           Print usage summary
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25       --verbose
26           Verbose module output
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28       --quiet
29           Quiet module output
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31       --ui
32           Force launching GUI dialog
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34   Parameters:
35       output=nameÂ [required]
36           Name for output raster map
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38       dimension=float
39           Fractal dimension of surface (2 < D < 3)
40           Default: 2.05
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42       number=integer
43           Number of intermediate images to produce
44           Default: 0
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DESCRIPTION

47       r.surf.fractal  creates a fractal surface of a given fractal dimension.
48       It uses the spectral synthesis method. The module can create intermedi‐
49       ate layers showing the build up of different spectral coefficients (see
50       Saupe, pp.106-107 for an example of this).
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52       This module generates naturally looking  synthetical  elevation  models
53       (DEM).
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NOTE

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

60       Generate surface using fractals in selected region, set color table and
61       display with shade.
62       g.region -p raster=elevation
63       r.surf.fractal output=fractals
64       r.colors map=fractals color=byr
65       r.relief input=fractals output=fractals_shade
66       d.mon wx0
67       d.shade shade=fractals_shade color=fractals b=50
68       Artificial surface created with fractals
69       Compare results when using different fractal dimensions:
70       # D=2.0005
71       g.region -dp
72       r.surf.fractal out=dem_d2_0005 dim=2.0005
73       r.info -r dem_d2_0005
74       r.mapcalc "dem_d2_0005_final = 1.0 * dem_d2_0005 + abs(min(dem_d2_0005))"
75       r.colors dem_d2_0005_final color=terrain
76       r.slope.aspect dem_d2_0005_final aspect=dem_d2_0005_final_as
77       # D=2.90
78       r.surf.fractal out=dem_d2_90 dim=2.90
79       r.info -r dem_d2_90
80       r.mapcalc "dem_d2_90_final = 1.0 * dem_d2_90 + abs(min(dem_d2_90))"
81       r.colors dem_d2_90_final color=terrain
82       r.slope.aspect dem_d2_90_final aspect=dem_d2_90_final_as
83       Artificial DEMs created with fractals:
84       top:  fractal  dimension  d=2.0005  (left: elevation map, right: aspect
85       map)
86       top: fractal dimension d=2.90 (left: elevation map, right: aspect map)
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REFERENCES

89       Saupe, D. (1988) Algorithms for random fractals, in  Barnsley  M.,  De‐
90       vaney  R.,  Mandelbrot B., Peitgen, H-O., Saupe D., and Voss R.  (1988)
91       The Science of Fractal Images, Ch. 2, pp.71-136. London:  Springer-Ver‐
92       lag.
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AUTHOR

99       Jo Wood, Midlands Regional Research Laboratory (ASSIST), University  of
100       Leicester
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SOURCE CODE

103       Available at: r.surf.fractal source code (history)
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105       Accessed: Saturday Jan 21 20:39:07 2023
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107       Main  index  | Raster index | Topics index | Keywords index | Graphical
108       index | Full index
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110       Â© 2003-2023 GRASS Development Team, GRASS GIS 8.2.1 Reference Manual
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114GRASS 8.2.1                                                  r.surf.fractal(1)