Description Usage Arguments Details Value Author(s) References See Also

Spatial and time variability indexes.

1 2 3 | ```
idwNear(surround, point, nmax, ...)
terrainIndex(surround, point)
tempIndex(runVals)
``` |

`surround` |
A |

`point` |
A |

`nmax` |
the number of nearest observations that should be used for the interpolation. |

`runVals` |
A |

`...` |
Additional arguments for |

`idwNear`

produces a deterministic interpolation at `point`

with the values of `surround`

.

`terrainIndex`

computes three spatial variability indexes: TRI,
PI, and roughness. Terrain Ruggedness Index is defined as the mean of
the absolute differences between a central cell and its surrounding 8
cells in a 3 by 3 grid. Topographic Position Index, is defined as the
difference between a central cell and the mean of its surrounding 8
cells in a 3 by 3 grid. Roughness is the largest inter-cell difference
of a central cell and its surrounding 8 cells in a 3 by 3 grid. The
results are normalized with the value at `point`

.

`tempIndex`

is a simple function that calculates the standard
deviation by rows.

A `data.frame`

Marcelo Pinho Almeida and Oscar Perpiñán Lamigueiro

Wilson, M. F., O’Connell, B., Brown, C., Guinan, J. C., & Grehan, A. J. (2007). Multiscale terrain analysis of multibeam bathymetry data for habitat mapping on the continental slope. Marine Geodesy, 30(1-2), 3-35.

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