R/LKrig.cov.plot.R

In LatticeKrig: Multi-Resolution Kriging Based on Markov Random Fields

# LatticeKrig  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

LKrig.cov.plot <- function(LKinfo, NP = 200, center = NULL, 
    xlim = NULL, ylim = NULL) {
    grid.info <- LKinfo$latticeInfo$rangeLocations
    if (is.null(xlim)) {
        xlim <-grid.info[,1]
    }
    ux <- seq(xlim[1], xlim[2], , NP)
    
    if (is.null(ylim)) {
        ylim <- grid.info[,2]
    }
    uy <- seq(ylim[1], ylim[2], , NP)
    
    if (is.null(center)) {
        center <- rbind(c(ux[NP/2], uy[NP/2]))
    }
    x1 <- cbind(ux, rep(center[2], NP))
    x2 <- rbind(center)
    d <- c(rdist(x1, x2))
    # evaluate the covariance from the LKinfo object devised from table
    # to approximate the Matern in the X direction
    y <- c(LKrig.cov(x1, x2, LKinfo))
    x1 <- cbind(rep(center[1], NP), uy)
    d2 <- c(rdist(x1, x2))
    
    # same in Y direction
    y2 <- c(LKrig.cov(x1, x2, LKinfo))
    return(list(d = cbind(d, d2), u = cbind(ux, uy), cov = cbind(y, 
        y2), center = center, LKinfo = LKinfo))
}