如何繪製柵格地圖上的值？

Question

我有一個美國的柵格地圖具有一定範圍的值，我進口

我要覆蓋的是來自一個CSV文件格式就可以了兩點：dput（droplevels（頭（點， 10）））：

points <- structure(list(lat = c(37.423333, 37.423333, 35.896667, 32.834722, 
32.834722, 32.834722, 32.834722, 32.834722, 32.834722, 32.834722 
), lon = c(-122.188333, -122.188333, -121.087222, -116.622222, 
-116.622222, -116.622222, -116.622222, -116.622222, -116.622222, 
-116.622222)), .Names = c("lat", "lon"), row.names = c(NA, 10L 
), class = "data.frame") 

等

我想fortify(prcp)但導致這一錯誤：

Error: ggplot2 doesn't know how to deal with data of class RasterLayer

我該怎麼辦？

TRY：

library(raster) 
library(sp) 

coordinates(points) = ~lon+lat 
proj4string(points) <- CRS("+proj=longlat +datum=WGS84 +ellps=WGS84 +towgs84=0,0,0") 


r <- getData("worldclim",var="bio",res=10) 
r<-r[[12]] #Annual Precipitation 
names(r) <- c("Prec") 
r <- crop(r, extent(-130, -60, 20, 60)) 
spplot(r) + layer(panel.points(x, y, col="green", cex=0.1, pch=1), data=points) 

但輸出全部爲綠色不知何故，即使點應該只有9000點。

Answer 1

嘗試這種解決方案：

library(raster) 
library(sp) 
library(latticeExtra) 

points <- structure(list(lat = c(37.423333, 37.423333, 35.896667, 32.834722, 
32.834722, 32.834722, 32.834722, 32.834722, 32.834722, 32.834722 
), lon = c(-122.188333, -122.188333, -121.087222, -116.622222, 
-116.622222, -116.622222, -116.622222, -116.622222, -116.622222, 
-116.622222)), .Names = c("lat", "lon"), row.names = c(NA, 10L 
), class = "data.frame") 

coordinates(points) = ~lon+lat 
proj4string(points) <- CRS("+proj=longlat +datum=WGS84 +ellps=WGS84 +towgs84=0,0,0") 

r <- getData("worldclim",var="bio",res=10) 
r<-r[[12]] #Annual Precipitation 
names(r) <- c("Prec") 
r <- crop(r, extent(-130, -60, 20, 60)) 

spplot(r)+spplot(points, col.regions="green")