'overlay' 不是 'namespace:sp' 的导出对象

Question

我有一些代码显示此错误，但是，我没有调用 "overlay"，可能是调用它的库函数

代码：

d.mle=likfit(P, ini.cov.pars = c(1,30), cov.model = 'matern', kappa = 0.5) 
d.mle

Xb = c(1, size, size, 1)
Yb = c(1, 1, size, size)
bordas = cbind(Xb, Yb)
polygon(bordas)
Ap = matrix(apply(bordas, 2, range))
gr <- expand.grid(x = seq(Ap[1, ], Ap[2, ], by = 1), y = seq(Ap[3, ], Ap[4, ], by = 1))
require(splancs)
gi <- polygrid(gr, borders = bordas) # delimita a area para interpolação
points(gi, pch = "+", col = 2)
KC  = krige.control(obj = d.mle, type.krige = "ok", lam = 1) 
d.k = krige.conv(P, loc = gr, krige = KC) #Realiza a interpolação por krigagem

valores_preditos = d.k$predict
Ze = matrix(valores_preditos, size, size) # Transforma os valores preditos em matriz
plot(Ze)
plot(image(X, Y, Ze, col = gray((0 : 4) / 4), breaks = c(a., b., c., d., e., f.)))

Answer 1

如果你这样做：

??overlay

...你应该得到一个包中提到单词 "overlay" 的所有函数的列表。当我这样做时，我看到两个具有该名称的函数，但我强烈怀疑它是您正在使用的代码所期望的 raster-package 版本。所以这样做：

install.packages('raster')
library(raster)
#re-run code

'overlay' 不是 'namespace:sp' 的导出对象

'overlay' is not an exported object from 'namespace:sp'

r

sp