Raster stack内データのslope, pvalueの計算
#STACK is a raster stack
ras=STACK1
iii <- which(!is.na(ras[]))
fun <- function(x) {
summary(lm(x ~ year))$coefficients}
A=apply(STACK[iii], 1, fun)
ras[iii]=A[1,]
STACK[iii].intercept=ras
ras[iii]=A[2,]
STACK[iii].slope=ras
ras[iii]=A[8,]
STACK[iii].pval=ras