r语言 - 如何提取光栅和点?

Question

我正在学习R并创建预测地图。在我的数据中，我有位置坐标。

如何提取我的光栅和点?

library(randomForest)
library(caret)
library(raster)
library(raster)
library(rgdal)
##-----load data 
data <- read.csv("0.10.coordinates.csv",sep=";", header = TRUE)
raster(swi.tif)
rsp.1<-raster("rsp.tif")
twi.1<-raster("twi.tif")
swi.1<-raster("swi.tif")
###load csv of 0-10cm sand,silt and clay %'s and lat/long (x,y) (in E: drive RF folder)
xy<-read.csv("0.10.coordinates.csv")
plot(swi.1)
plot(twi.1)
plot(swi.1)
plot(rsp.1)
stack(swi.1,rsp.1,twi.1,xy)
topo.brick<-brick(rsp.1,swi.1,twi.1,xy)
brick(rsp.1,twi.1,swi.1,data) 
df<-extract(data,rsp.1,twi.1,swi.1)`
Error in (function (classes, fdef, mtable)  : 
unable to find an inherited method for function ‘extract’ for signature ‘"data.frame", "RasterLayer"’

Answer 1

查看?raster::extract，了解需要哪些输入以及以什么顺序输入。在任何情况下，您都应该创建一个可复制的示例。但是，这里有一个虚拟数据的示例:

library(raster)
# with raster -------------------------------------------------------------
r <- s <- t <- raster()
r[] <- 1:ncell(r)
s[] <- sample(1:10,ncell(s),replace = T)
t[] <- runif(ncell(t))
stacked <- stack(r,s,t)
#points
xy <- cbind(-50, seq(-80, 80, by=20))
#extract
ex <- extract(stacked,xy, df=TRUE)

如果提取时间太长，请检查terra::extract或更好的exactextractr::exact_extract。

Answer 2

请参阅Elia的示例，但从我从您的代码中收集到的信息来看，您应该能够执行

library(raster)
xy <- read.csv("0.10.coordinates.csv")
s <- stack("rsp.tif", "twi.tif", "swi.tif")
d <- extract(s, xy)`