Question

我有一个由12层组成的栅格砖，每层代表给定月份的平均温度（第1层= 1月，第2层= 2月等）。我想要做的就是计算一些简单的统计数据，例如平均值和标准偏差。这是一个问题：我只想计算与小麦作物季节持续时间相对应的月份的这些统计数据，并删除所有其他单元格值（即将它们更改为NA）。我有一个小麦种植日期rasterLayer和一个小麦收获日期rasterLayer（这两个光栅层的细胞值再次代表小麦种植和收获的一年中的月份）。

我已经通过以下代码成功实现了这一目标，但只有当小麦种植的时间早于收获时（即作物不跨越两年，例如 - 种植于2015年11月（11日）并收获2016年4月（4））。

种植RasterLayer https://www.dropbox.com/s/d5i8kdfxl2hzulc/WPlantingCropped.gri?dl=0

Harvest RasterLayer https://www.dropbox.com/s/idqys2djbgjv4yr/WHarvestCropped.gri?dl=0

最低温度RasterBrick https://www.dropbox.com/s/7pf5oe5rjcaqdqt/TminCropped.gri?dl=0

  Harvest<-raster("WHarvestCropped")
  Planting<-raster("WPlantingCropped")
  TminCropped<-raster("TminCropped)

#Split dataset into two: Separate those cells in which wheat is planted earlier than 
#its harvest date from those in which wheat is planted later than its harvest date 

  Separate<-overlay(Planting,Harvest, fun=function (x,y) {return(x-y)},filename="Separate")

  Earlier<-function(x){
    ifelse(x<0,1,
           ifelse(x>=0,NA,NA))}

  EarlierPH<-calc(Separate,Earlier, filename="EarlierPH")

#Make Planting dataset consisting of only those cells in which wheat is planted earlier than harvest      

  EarlierPlant<-overlay(EarlierPH,Planting,fun=function (x,y) {return(x*y)}, 
                       filename="EarlierPlant",overwrite=T,na.rm=T)

#Make Harvest dataset consisting of only those cells in which wheat is planted later than harvest  

  EarlierHarvest<-overlay(EarlierPH,Harvest, fun=function (x,y){return(x*y)}, 
                        filename="EarlierHarvest",overwrite=T,na.rm=T)


#Expand planting and harvest rasterLayers into RasterBricks

  Expand <- function(p) {
   x <- matrix(0, nrow=length(p), ncol=12)
   x[cbind(1:nrow(x), p)] <- 1
   x <- t(apply(x, 1, cumsum))
   x[x==0] <- 0
   x
  }

  EarlyPlantingBrick<-calc(EarlierPlant,Expand,filename="EarlyPlantingBrick",overwrite=T)
  EarlyHarvestBrick <- calc(EarlierHarvest, Expand, filename="EarlyHarvestBrick",overwrite=T)

  EarlyPHJoin<-overlay(EarlyPlantingBrick,EarlyHarvestBrick, 
                      fun=function(x,y){return(x+y)}, filename="EarlyPHJoin",overwrite=T)

#Final cropping calendar template

  i <- function(f) {
    x<-f
    x[x==2]<-0
    return(x)
  }

  EarlyBrickTemplate<-calc(EarlyPHJoin, i, filename="EarlyBrickTemplate",overwrite=T)

#Final Cropping Calendar for cells in which wheat was planted earlier than harvest

  EarlyBrick <-overlay(EarlyBrickTemplate,TminCropped, 
                      fun=function(x,y){return(x*y)}, filename="EarlyBrick”,overwrite=T)

同样，上述代码适用于小麦播种日期早于收获日期（即小麦在一年内种植和收获）的细胞，但不适用于小麦播种日期早于其收获的月份日期（例如，2015年11月种植，2016年4月收获）。我怎么能这样做？

基于另一个rasterLayer

0 个答案: