Question

我想对空间网格数据框进行简单的操作。考虑我需要知道每个空间点（此处为行）的每列的总和。不幸的是，我无法使用sum或rowSums函数来做到这一点。你能帮帮我怎么做吗？我搜索了很多，但实际上并没有看到任何类似的情况。

我的数据摘要是：

 FLint
 Object of class SpatialGridDataFrame
Object of class SpatialGrid
Grid topology:
  cellcentre.offset cellsize cells.dim
x          582228.8 9.071439       568
y         4505538.0 9.071439       445
SpatialPoints:
                 x       y
     [1,] 582228.8 4509566
     [2,] 582237.9 4509566
     ....
  Data summary:
 Deterministic        sim001           sim002                   
 Min.   :1        Min.   :1        Min.   :1               
 1st Qu.:1        1st Qu.:1        1st Qu.:1             
 Median :1        Median :1        Median :1               
 Mean   :1        Mean   :1        Mean   :1               
 3rd Qu.:1        3rd Qu.:1        3rd Qu.:1              
 Max.   :1        Max.   :1        Max.   :1               
 NA's   :220354   NA's   :220354   NA's   :220354

在这里，我尝试了很多例子，例如最后两列：

y2 <- rowSums (FLint[,2:3], na.rm = TRUE, dims = 1)
Error in base::rowSums(x, na.rm = na.rm, dims = dims, ...) : 
 'x' must be an array of at least two dimensions

Answer 1

我对您是否需要rowSums()或colSums()感到有些困惑，但两者都会以相同的方式使用：

您需要在S4对象的rowSums()位置上调用data

这是一个玩具示例

library(sp)

## data taken from ?SpatialGridDataFrame
data(meuse.grid) # only the non-missing valued cells
coordinates(meuse.grid) = c("x", "y") # promote to SpatialPointsDataFrame
gridded(meuse.grid) <- TRUE # promote to SpatialPixelsDataFrame
x = as(meuse.grid, "SpatialGridDataFrame")

## the data is contained in '@data'
rowSums(x@data[, c("part.a", "part.b")], na.rm = T)

因此，在您的示例中，我认为您想要

rowSums(Flint@data[, 2:3])

如果查看结构

，您可以看到数据的位置

str(x)
Formal class 'SpatialGridDataFrame' [package "sp"] with 4 slots
  ..@ data       :'data.frame': 8112 obs. of  5 variables:
  .. ..$ part.a: num [1:8112] NA NA NA NA NA NA NA NA NA NA ...
  .. ..$ part.b: num [1:8112] NA NA NA NA NA NA NA NA NA NA ...
  .. ..$ dist  : num [1:8112] NA NA NA NA NA NA NA NA NA NA ...
  .. ..$ soil  : Factor w/ 3 levels "1","2","3": NA NA NA NA NA NA NA NA NA NA ...
  .. ..$ ffreq : Factor w/ 3 levels "1","2","3": NA NA NA NA NA NA NA NA NA NA ...
  ..@ grid       :Formal class 'GridTopology' [package "sp"] with 3 slots
  .. .. ..@ cellcentre.offset: Named num [1:2] 178460 329620
  .. .. .. ..- attr(*, "names")= chr [1:2] "x" "y"
  .. .. ..@ cellsize         : Named num [1:2] 40 40
  .. .. .. ..- attr(*, "names")= chr [1:2] "x" "y"
  .. .. ..@ cells.dim        : Named int [1:2] 78 104
  .. .. .. ..- attr(*, "names")= chr [1:2] "x" "y"
  ..@ bbox       : num [1:2, 1:2] 178440 329600 181560 333760
  .. ..- attr(*, "dimnames")=List of 2
  .. .. ..$ : chr [1:2] "x" "y"
  .. .. ..$ : chr [1:2] "min" "max"
  ..@ proj4string:Formal class 'CRS' [package "sp"] with 1 slot
  .. .. ..@ projargs: chr NA

对spatialGridDataFrame求和：rowSums或colSums

1 个答案: