spEMD {spemd}

spEMD

Description

2D EMD for spatial objects

Usage

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.

Value

.

Author(s)

Pierre Roudier

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")])
}

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