Creates a two-dimensional fractional Brownian motion neutral landscape model.

nlm_fbm(ncol, nrow, resolution = 1, fract_dim = 1, user_seed = NULL,
rescale = TRUE, ...)

## Arguments

ncol |
[`numerical(1)` ]
Number of columns forming the raster. |

nrow |
[`numerical(1)` ]
Number of rows forming the raster. |

resolution |
[`numerical(1)` ]
Resolution of the raster. |

fract_dim |
[`numerical(1)` ]
The fractal dimension of the process (0,2) |

user_seed |
[`numerical(1)` ]
Set random seed for the simulation |

rescale |
[`numeric(1)` ]
If `TRUE` (default), the values are rescaled between 0-1. |

... |
Other options to RandomFields::RFoptions, especially if using
a fractal dimension between ~ 1.6 and 1.9 one must set the option
`modus_operandi = "sloppy"` . |

## Value

RasterLayer

## Details

Neutral landscapes are generated using fractional Brownian motion,
an extension of Brownian motion in which the amount of correlation between
steps is controlled by `frac_dim`

. A high value of `frac_dim`

produces a
relatively smooth, correlated surface while a low value produces a rough, uncorrelated one.

## References

Travis, J.M.J. & Dytham, C. (2004). A method for simulating patterns of
habitat availability at static and dynamic range margins. *Oikos* , 104, 410–416.

Martin Schlather, Alexander Malinowski, Peter J. Menck, Marco Oesting,
Kirstin Strokorb (2015). nlm_fBm. *Journal of Statistical
Software*, 63(8), 1-25. URL http://www.jstatsoft.org/v63/i08/.

## Examples

# simulate fractional brownian motion
fbm_raster <- nlm_fbm(ncol = 20, nrow = 30, fract_dim = 0.8)

# NOT RUN {
# visualize the NLM
landscapetools::show_landscape(fbm_raster)
# }