Smooth2D.Rd

% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/Smooth2D.R
\name{Smooth2D}
\alias{Smooth2D}
\alias{smooth_dct}
\alias{smooth_svd}
\title{Smooths a 2D field}
\usage{
Smooth2D(x, y, value, method = smooth_svd(0.01))

smooth_dct(kx = 0.5, ky = kx)

smooth_svd(variance_lost = 0.01)
}
\arguments{
\item{x, y}{Vector of x and y coordinates}

\item{value}{Vector of values}

\item{method}{The method to use smooth. Must be a function that takes a matrix
and returns the smoothed matrix. Build-in methods are \code{smooth_svd()} and \code{smooth_dct()}.}

\item{kx, ky}{Proportion of components to keep in the x and
y direction respectively. Lower values increase the smoothness.}

\item{variance_lost}{Maximum percentage of variance lost after smoothing.}
}
\value{
A vector of the same length as value.
}
\description{
Smooth a 2D field using a user-supplied method.
}
\details{
\code{smooth_svd()} computes the SVD of the field and reconstructs it keeping only
the leading values that ensures a maximum variance lost.
\code{smooth_dct()} computes the Discrete Cosine Transform of the field and sets
a proportion of the components to zero.
}
\examples{
library(ggplot2)
# Creates a noisy version of the volcano dataset and applies the smooth
volcano <- reshape2::melt(datasets::volcano, value.name = "original")
volcano$noisy <- with(volcano, original + 1.5*rnorm(length(original)))

volcano$smooth_svd <- with(volcano, Smooth2D(Var2, Var1, noisy, method = smooth_svd(0.005)))
volcano$smooth_dct <- with(volcano, Smooth2D(Var2, Var1, noisy, method = smooth_dct(kx = 0.4)))

volcano <- reshape2::melt(volcano, id.vars = c("Var1", "Var2"))

ggplot(volcano, aes(Var1, Var2)) +
  geom_contour(aes(z = value, color = after_stat(level))) +
  scale_color_viridis_c() +
  coord_equal() +
  facet_wrap(~variable, ncol = 2)
}