Question

我有一些栅格，我想计算移动平均线，然后再次重写栅格。

  r1 <- r2 <- r3 <- r4 <- r5 <- r6 <- raster(nrows=10, ncols=10);
  r1 <- setValues(r1,runif(100,min=1,max=100));
  r2 <- setValues(r2,runif(100,min=1,max=100));
  r3 <- setValues(r3,runif(100,min=1,max=100));
  r4 <- setValues(r4,runif(100,min=1,max=100));
  r5 <- setValues(r5,runif(100,min=1,max=100));
  r6 <- setValues(r6,runif(100,min=1,max=100));
  # Stack them
  st1 <- stack(r1,r2,r3,r4,r5,r6)
  #compute the moving average:
  x <- calc(st1, function(x) movingFun(x, 3, mean))

现在x中的图层应重新计算为：

  firstlayer=(first layer + fourth layer)/2
  secondlayer=(second layer + fifth layer)/2
  thirdlayer=(third layer + sixth layer)/2

这些是示例，但我的数据不止于此，所以无论我在x

中有多少层，我都更喜欢使用循环来完成工作

Answer 1

您可以这样做：

  library(raster)
  # creating the same data set, but in fewer lines
  r <- raster(nrows=10, ncols=10)
  s <- stack(lapply(1:6, function(...) setValues(r, runif(100,min=1,max=100))))
  x <- calc(st1, function(x) movingFun(x, 3, mean))

  # remove the edges to line up the layers that need to be added
  nl <- nlayers(x)
  x1 <- x[[-c((nl-2):nl)]]  
  x2 <- x[[-c(1:3)]]

  z <- x1 + x2 / 2

请参阅？stackApply了解其他一些案例

堆叠后如何操纵栅格？

1 个答案: