【R语言】根据经纬度从tif图像中提取兴趣点

library(stringr)
library(raster)
library(sp)

#set work space
getwd()
setwd("G:/data")

#初始设置，提取点
lai <- matrix(nr=50,nc=2)
point<-cbind(128.5,45.9) #lon,lat

i <- 1
n <- 1
repeat {
  #读取栅格文件
  dataname = str_c("2004/A",2004*1000+i,".tif")
  data<-raster(dataname)
  
  #提取兴趣点
  lai[n,1] <- i
  lai[n,2] <- extract(data, point)
  
  i <- i+8
  n <- n+1
  
  if(i > 366) {
    break
  }
}