spEMD function

spEMD

2D EMD for spatial objects

spEMD(data, zcol = "z", method = "splines", n.imf.max = 10,
  n.sp.max = 5, n.extrema.min = 1, stoprule = "mean.imf",
  stoprule.extrema = TRUE, thresh.extrema = 1, tol = 0,
  diff.nb.extrema = 0.05, abs.nb.extrema = 5, nb.nn = 4,
  n.pts.spline = 4, neig = NULL, save_neig = TRUE, verbose = TRUE)

Arguments

• data: Input dataset, either a data.frame or a Spatial*DataFrame
• zcol: Name of the column containing the attribute of interest.
• method: Interpolation method. Currently only splines is supported.
• n.imf.max: Maximum depth of decomposition (maximum number of IMF).
• n.sp.max: Number of iterations in the sifting process.
• n.extrema.min: Minimum number of extrema.
• stoprule: Rule used to stop the EMD process. Currently only mean.imf is implemented.
• stoprule.extrema: Should spEMD checks for the number of extrema to be similar? Defaults to TRUE.
• thresh.extrema: Significative threshold for the extrema. Defaults to 1.
• tol: Value that the avergae of the IMF candidate need to reach so to be considered as a valid IMF.
• diff.nb.extrema: Percentage limit difference maxima/minima. If smaller, more permissive on the mean of the IMF candidate.
• abs.nb.extrema: Absolute difference between number of extrema.
• nb.nn: Number of nearest neighbours to take into account (when data is on a regular grid).
• n.pts.spline: Number of points to locally interpolate IMFs.
• neig: Option the re-use a formerly existing neig object in order to save time.
• save_neig: Option to save the neig object as a .RData file once created.
• verbose: Prints progress information messages. Defaults to TRUE.

Returns

.

Examples

# Getting sample data from the gstat package
if (require(gstat)) {
library(sp)

# Example for gridded data
data(ncp.grid, package = 'gstat')
coordinates(ncp.grid) <- ~x+y
gridded(ncp.grid) <- TRUE
res.ncp <- spEMD(ncp.grid, zcol = "depth", thresh.extrema = 0.1, verbose = FALSE)

# Plot results
spplot(res.ncp[, c('imf1', "imf2", "imf3")])
}

#

Author(s)

Pierre Roudier