如何在栅格地图上绘制值？

Question

我有一张美国栅格地图，其中包含我导入的特定值范围

我希望以这种格式叠加来自CSV文件的点：dput（droplevels（head（points，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

我尝试fortify(prcp)，但这导致了这个错误：

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

我该怎么办？

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)

但即使点数应该只有9000点，输出也是绿色的。

Answer 1

试试这个解决方案：

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")