使用 terra 在多面板栅格上绘制 shapefile

Question

我有四个光栅和一个形状文件。我想在单个面板中的 4 个栅格之上绘制 shapefile

  library(terra)
  r1 <- r2 <- r3 <- r4 <- rast(ncol=10, nrow=10, xmin=-150, xmax=-80, ymin=20, ymax=60)
  
  values(r1) <- runif(ncell(r1))
  values(r2) <- runif(ncell(r2))
  values(r3) <- runif(ncell(r3))
  values(r4) <- runif(ncell(r4))

  rr <- c(r1, r2, r3, r4)
  
  # shapefile 
  lon <- c(-116.8, -114.2, -112.9, -111.9, -114.2, -115.4, -117.7)
  lat <- c(41.3, 42.9, 42.4, 39.8, 37.6, 38.3, 37.6)
  lonlat <- cbind(lon, lat)
  pols <- vect(lonlat, type="polygons", crs="epsg:4326")
  
  terra::plot(rr)      
  terra::plot(pols, add = T)      

但是，shapefile 并未添加到栅格中，而是绘制在中间。

Answer 1

您的示例数据

library(terra)
r <- rast(ncol=10, nrow=10, nlyr=4, xmin=-150, xmax=-80, ymin=20, ymax=60) 
values(r) <- 1:size(r)
# polygons
lon <- c(-116.8, -114.2, -112.9, -111.9, -114.2, -115.4, -117.7)
lat <- c(41.3, 42.9, 42.4, 39.8, 37.6, 38.3, 37.6)
pols <- vect(cbind(lon, lat), type="polygons", crs="+proj=longlat +datum=WGS84")
  

解决方案

plot(r, fun=function()lines(pols))