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24, chemin de Borde Rouge -Auzeville - CS52627 31326 Castanet Tolosan cedex - France

Last update: May 2021

Menu Logo Principal

Soil Science Research Unit


The GARS software

« Generate A Rough Surface »

Rugosite © INRA

The shape of a surface controls numerous phenomena (alteration, flow, etc.), from the microscopic scale to the scale of the landscape.

While our laboratory is equipped to measure the roughness of soil surface with a millimeter resolution, it is sometimes useful to generate surfaces numerically. Hence, on can control its properties and generate numerous statistically-identical surfaces.

Measured © INRA
Generated © INRA

Surface measured in the field                                                 Surface generated with GARS

The surfaces generated with GARS can look like very much to surfaces measured in the field.

Dark gray: low height.   Light gray: high height.

Generation method

The surface generated with GARS can include:

  • A random change generated by inverse Fourier transform in 2 dimensions. The power spectrum (slope, correlation length) can be set, the phase spectrum being random.
  • A general slope, which value and direction is set by the user.
  • A sinusoidal wave which characteristics (amplitude, wave length and direction) can be parameterized.T


You can try GARS on line.
To be kept informed of the changes of GARS, ask for a subscription to the diffusion list GARS-infos@ by sending an email to

GARS : a free source code

GARS is a free software distributed under the license CeCILL-B (BSD-compatible). Hence, you can access to the whole source code (in C), and you are free to use it and to modify it as long as you cite it.
In practice, to make your improvements known to the community, the simplest way is to integrate directly your code lines into GARS: contact us at

Distribution : Free source code, in English.

Download: Source code

Documentation and information : Help on GARS

Contact : Frédéric DARBOUX

See also :
FullSWOF, a code simulating flows and that can use surfaces generated by GARS as an input
Rugosimetry laser, a tool to measure a surface with a 0.5 mm resolution.