R/createxymap.R

In BayesX: R Utilities Accompanying the Software Package BayesX

createxymap <- function(x, y, districts = NULL, p = 2, max.dist) {
  
  if (length(x) != length(y)) 
    stop("Lengths of x and y differ!")
  
  if (p < 1) 
    stop("p have to be p >= 1!")
  
  S <- length(x)
  if (is.null(districts)) 
    districts <- paste(seq(1, S))
  
  ## gra format
  gra <- matrix(0, S, S)
  
  if (p == Inf) {
    for (i in 1:(S - 1)) {
      for (j in (i + 1):S) {
        xdiff <- x[j] - x[i]
        ydiff <- y[j] - y[i]
        
        if (max(abs(xdiff), abs(ydiff)) <= max.dist) {
          gra[i, j] <- gra[j, i] <- -1
        }
      }
    }
  } else {
    for (i in 1:(S - 1)) {
      for (j in (i + 1):S) {
        xdiff <- x[j] - x[i]
        ydiff <- y[j] - y[i]
        
        if (((abs(xdiff))^p + (abs(ydiff))^p)^(1/p) <= max.dist) {
          gra[i, j] <- gra[j, i] <- -1
        }
      }
    }
  }
  
  diag(gra) <- -apply(gra, 1, sum)
  
  rownames(gra) <- districts
  colnames(gra) <- districts
  
  class(gra) <- "gra"
  
  ## bnd format
  x.range <- max(x) - min(x)
  y.range <- max(y) - min(y)
  step <- max(x.range, y.range)/100
  x.range <- x.range + 2 * step
  y.range <- y.range + 2 * step
  height2width <- round(y.range/x.range, digits = 2)
  
  bnd <- list()
  for (i in 1:S) {
    bnd[[i]] <- matrix(data = c(x[i] - step, y[i] - step, x[i] - step, y[i] + 
      step, x[i] + step, y[i] + step, x[i] + step, y[i] - step, x[i] - step, 
      y[i] - step), byrow = T, nrow = 5, ncol = 2)
  }
  
  names(bnd) <- districts
  
  attr(bnd, "surrounding") <- replicate(n = length(bnd), expr = character())
  attr(bnd, "height2width") <- height2width
  class(bnd) <- "bnd"
  
  maps <- list(gra, bnd)
  names(maps) <- c("gra", "bnd")
  return(maps)
}