在R不兼容类型中替换空间多边形数据框中的值

我正在使用R中的

sp

包对多边形中的点属性进行相当简单的聚合（即

SpatialPointsDataFrame

中的

SpatialPointsDataFrame

）。我相信我可以毫无问题地做到这一点。但是，为了绘制“更漂亮”的图，我想用数字0替换没有出现点的聚集区域（使用

aggregate

函数后给定NAs）。执行此操作时，我收到错误：

---

[使用
countyAgg[naIndex，“Att”]中出现错误谢谢！我知道这很简单。我非常感谢您的帮助！
library(sp)
library(raster)

### Get Washington County map ###
USCounty <- raster::getData('GADM', country='USA', level=2) # Download US County Map
WA <- USCounty[USCounty$NAME_1 == "Washington",] # Subset data to just the State of WA

### Create point data ###

# Set parameters
numPts <- 30 # Set the number of points

# Set projection I want
ptsCRS <- "+proj=aea +lat_1=29.5 +lat_2=45.5 +lat_0=23 +lon_0=-96 +x_0=0 +y_0=0 +datum=NAD83 +units=m +no_defs +ellps=GRS80 +towgs84=0,0,0"

# Project data
WA <- spTransform(WA, ptsCRS)

# Create point coordinates and attribute data
set.seed(22)
x <- sample(xmin(WA):xmax(WA), numPts, replace = TRUE) #xvalues in the extent of the state
y <- sample(ymin(WA):ymax(WA), numPts, replace = TRUE) #yvalues in the extent of the state
ptsCoords <- cbind(x,y) # Store the coordinates
ptsData <- data.frame(Att = rnorm(numPts, 7, 1)) # Create and store attribute data

pts <- SpatialPointsDataFrame(ptsCoords, data = ptsData, proj4string = crs(WA))

# Plot the data
plot(WA)
plot(pts, add = TRUE)

### Perform Aggregation of point attributes by WA polygons ###
countyAgg <- aggregate(pts[WA, "Att"], WA, sum)

### Plot Data ###
spplot(countyAgg)

# Find NAs
naIndex <- which(is.na(countyAgg$Att))

# Replace with zeroes
countyAgg[naIndex,]$Att <- 0

R> class(countyAgg[naIndex,]$Att)
[1] "numeric"
R> class(countyAgg[naIndex, "Att"])
[1] "SpatialPolygonsDataFrame"
attr(,"package")
[1] "sp"