## ---- echo=FALSE, include=FALSE-----------------------------------------------
library(knitr)
opts_chunk$set(fig.width = 5, fig.height = 5, fig.cap='',  collapse = TRUE)



## -----------------------------------------------------------------------------
library(raster)
r <- raster(ncol=10, nrow=10, xmx=-80, xmn=-150, ymn=20, ymx=60)
r


## -----------------------------------------------------------------------------
values(r) <- runif(ncell(r))
r


## -----------------------------------------------------------------------------
values(r) <- 1:ncell(r)
r


## ---- plot4-1, fig.height=4---------------------------------------------------
plot(r)

# add polygon and points
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 <- spPolygons(lonlat, crs='+proj=longlat +datum=WGS84')

points(lonlat, col='red', pch=20, cex=3)
plot(pols, border='blue', lwd=2, add=TRUE)



## ---- plot4-2, fig.height=6.8, fig.width=9------------------------------------
r2 <- r * r
r3  <- sqrt(r)
s <- stack(r, r2, r3)
s
plot(s)


## -----------------------------------------------------------------------------
b <- brick(s)
b