Revision 370c1161f275c7f191e9326102bfd61cae62d545 authored by Douglas Nychka on 11 May 2017, 17:23:03 UTC, committed by cran-robot on 11 May 2017, 17:23:03 UTC
1 parent 67f03a5
smooth.2d.R
# fields is a package for analysis of spatial data written for
# the R software environment .
# Copyright (C) 2016
# University Corporation for Atmospheric Research (UCAR)
# Contact: Douglas Nychka, nychka@ucar.edu,
# National Center for Atmospheric Research, PO Box 3000, Boulder, CO 80307-3000
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with the R software environment if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
# or see http://www.r-project.org/Licenses/GPL-2
"smooth.2d" <- function(Y, ind = NULL, weight.obj = NULL,
setup = FALSE, grid = NULL, x = NULL, nrow = 64, ncol = 64,
surface = TRUE, cov.function = gauss.cov, Mwidth = NULL,
Nwidth = NULL, ...) {
temp <- as.image(Y, ind, grid = grid, nx = nrow, ny = ncol,
x = x)
Y <- temp$z
NN <- temp$weights
grid <- list(x = temp$x, y = temp$y)
if (is.null(weight.obj)) {
dx <- grid$x[2] - grid$x[1]
dy <- grid$y[2] - grid$y[1]
m <- length(grid$x)
n <- length(grid$y)
if (is.null(Mwidth))
M <- 2 * m
else {
M <- m + Mwidth
}
if (is.null(Nwidth))
N <- 2 * n
else {
N <- n + Nwidth
}
xg <- make.surface.grid(list((1:M) * dx, (1:N) * dy))
center <- matrix(c((dx * M)/2, (dy * N)/2), nrow = 1,
ncol = 2)
out <- cov.function(xg, center, ...)
out <- as.surface(xg, c(out))$z
temp <- matrix(0, nrow = M, ncol = N)
temp[M/2, N/2] <- 1
wght <- fft(out)/(fft(temp) * M * N)
weight.obj <- list(m = m, n = n, grid = grid, N = N,
M = M, wght = wght, call = match.call())
if (setup) {
return(weight.obj)
}
}
temp <- matrix(0, nrow = weight.obj$M, ncol = weight.obj$N)
temp[1:m, 1:n] <- Y
temp[is.na(temp)] <- 0
temp2 <- Re(fft(fft(temp) * weight.obj$wght, inverse = TRUE))[1:weight.obj$m,
1:weight.obj$n]
temp <- matrix(0, nrow = weight.obj$M, ncol = weight.obj$N)
temp[1:m, 1:n] <- NN
temp[is.na(temp)] <- 0
temp3 <- Re(fft(fft(temp) * weight.obj$wght, inverse = TRUE))[1:weight.obj$m,
1:weight.obj$n]
if (!surface)
(temp2/temp3)
else {
list(x = weight.obj$grid$x, y = weight.obj$grid$y, z = temp2/temp3,
index = ind)
}
}
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