rp.geosim: Interactive visualisation of spatially correlated random...

In rpanel: Simple Interactive Controls for R using the 'tcltk' Package

Interactive visualisation of spatially correlated random fields

Description

This function allows Gaussian random fields to be simulated and visualised, using graphical controls for a variety of parameter settings.

Usage

rp.geosim(max.Range = 0.5, max.pSill = 1, max.Nugget = 1, max.Kappa = 10, 
                      max.aniso.ratio = 5,
                      min.ngrid = 10, max.ngrid = 25, hscale = NA, vscale = hscale,
                      col.palette = terrain.colors(40))

Arguments

max.Range, max.pSill, max.Nugget	the maximum values of the range, sill and nugget parameters. These define the end-points of the corresponding slider scales.
max.Kappa	The maximum value of the kappa parameter in the Matern family of spatial covariance functions.
max.aniso.ratio	The maximum value of the anisotropy ratio parameter, which controls the degree of anisotropy in the simulated field.
min.ngrid, max.ngrid	the minimum and maximum values of the grid size for sampling points.
hscale, vscale	horizontal and vertical scaling factors for the size of the plots. It can be useful to adjust these for different screen resolutions or for projection in a lecture setting. The default values are 1.2 on Unix platforms and 1.4 on Windows platforms.
col.palette	the colour palette used to display the random fields.

Details

The aim of the tool is to allow the generation of repeated simulated fields without the distraction of re-executing code explicitly. This can help to gain an intuitive understanding of the nature of spatial data. In particular, interactive control of parameters can help greatly in understanding the meaning and effects of parameter values. Nugget effects can be added and sampled points displayed. Two-dimensional contour plots are produced. Three-dimensional plots are also produced if the rgl package is available.

The use of the function is discussed in the paper paper by Bowman et al. (2008) referenced below.

The geoR and RandomFields packages are used to generate the data.

Note that the Matern covariance function is parameterised in the form described by Handcock & Wallis (1994) which separates the effects of the shape and range parameters.

Value

Nothing is returned.

References

Adler, D. (2005). rgl: 3D Visualization Device System (OpenGL). https://cran.r-project.org.

Bowman, A.W., Crawford, E., Alexander, G. Gibson and Bowman, R.W. (2007). rpanel: Simple interactive controls for R functions using the tcltk package. Journal of Statistical Software, 17, issue 9.

Bowman, A.W., Gibson, I., Scott, E.M. and Crawford, E. (2008). Interactive Teaching Tools for Spatial Sampling. Journal of Statistical Software, 36, 13, 1–17.

Diggle, P.J. and Ribiero, P.J. (2008). Model-based Geostatistics. Springer, New York.

Handcock, M.S. and Wallis, J.R. (1994). An approach to statistical spatial-temporal modeling of meteorological fields. Journal of the American Statistical Association, 89, 368-378.

See Also

rp.firth, rp.mururoa

Examples

## Not run: 
   rp.geosim()

## End(Not run)

rpanel documentation built on Feb. 16, 2023, 10:37 p.m.