0

我想知道将地形纳入 R 中相关随机游走的可能性有哪些。我有研究区域的数字高程模型 (DEM)。我想在我的随机行走中避开陡峭斜坡的区域。

walk <- function(x0, y0, head0, n, parameterMu, parameterRho, parameterMean, parameterSd)
{
  # Get nr of individuals, call it k
  k = length(x0)

  # Create list to hold data
  all.paths <- list()
  
  for (j in 1:k)
  {
    # Create structure to hold data
    steps <- data.frame(matrix(0,n,6))
    colnames(steps) <- c("id","x", "y", "steplength", "heading", "turningangle")
    
    # Insert the id, starting location and heading
    steps[,"id"] = j
    steps[1,"x"] = x0[j]
    steps[1,"y"] = y0[j]
    steps[1,"heading"] = head0[j]
    
    # Simulate steps
    for(i in 2:n)
    {
      # Draw step length and turning angle, compute heading
      steplength = rnorm(n = 1, mean = parameterMean, sd = parameterSd)
      turningangle = as.numeric(rwrappedcauchy(n = 1, mu = parameterMu, rho = parameterRho))
      newbearing = as.numeric(circular(steps[i-1,"heading"]) + circular(turningangle)) %% (2*pi)
      
      # Get new location
      next.xy <- movement(x0=steps[i-1,"x"], y0=steps[i-1,"y"], step=steplength, heading=newbearing)
      
      # Store output (xy on row i, steplength/heading on row i-1)
      steps[i,"x"] <- next.xy[1,"x"]
      steps[i,"y"] <- next.xy[1,"y"]
      steps[i,"steplength"] <- next.xy[1,"step"]
      steps[i,"heading"] <- newbearing
      steps[i,"turningangle"] <- turningangle
        
    # Store trajectory in list
    all.paths[[j]] <- steps
  }
  
  # Return output
  return(all.paths)
}

运动功能：

movement <- function(x0, y0, step, heading)
{
  x_new <- x0 + sin(heading)*step
  y_new <- y0 + cos(heading)*step
  move.temp <- data.frame(x = x_new,
                          y = y_new,
                          step = step,
                          head = heading)
  return(move.temp)
}
4

0 回答 0