R/f.pixelcovmat.R

In constrainedKriging: Constrained, Covariance-Matching Constrained and Universal Point or Block Kriging

f.pixelcovmat<- function(
  pixgrid,    ### grid information like mesh size positioin and so on..
  model)### parameter of the covariance
## purpose: calculate the cov matrix for all rectangles within
##          the boundingbox
## arguments:
##
##
## author: Ch. Hofer
## date: 25. Jan 2007
{
  t.dim  <- pixgrid$pixgridInfo$nrows * pixgrid$pixgridInfo$ncols
  #pixcm = PixelKovarianzmatrix
  pixcm <- matrix(0, nrow = t.dim , ncol = t.dim)
  #
  t.pixel.area <- pixgrid$pixgridInfo$rowwidth * pixgrid$pixgridInfo$colwidth
  #
  ## build covariance matrix of the pixels defined by pixgrid
  t.q <- 1
  for(i in 1:length( model ) )
  {
    if(model[[ i ]]$model == "nugget")
    {
      diag( pixcm ) <- rep( 1, length( diag( pixcm ) ) ) * (model[[ i ]]$variance / t.pixel.area) + diag( pixcm)
    }
    else
    {
      pixcm <-  computeV( pixgrid$pixgridInfo,
        class = "special",
        params = model[[ i ]]
      ) * model[[ i ]]$variance + pixcm
      t.q <- t.q + 1
    } # end if
  } # end for
  return( pixcm )
} ### end of function