Single colorkey for raster and points Levelplot R

Question

Using the sample data below, how can I generate rasters and spatial points plot with the same colorkey as in the "manually" joined plot shown below?

library(rasterVis)
library(raster)
library(colorRamps)
col=colorRampPalette(matlab.like2(255))

s <- stack(replicate(2, raster(matrix(runif(100), 10))))
xy <- data.frame(coordinates(sampleRandom(s, 10, sp=TRUE)),
                 z1=runif(10), z2=runif(10))

levelplot(s, margin=FALSE, at=seq(0, 1, 0.05),col.regions=col)
x=xy$x;y=xy$y;z=xy$z1

levelplot(z ~ x + y,contour=F, panel = panel.levelplot.points, 
          margin=FALSE,col.regions=col,
          par.settings=list(axis.line=list(lwd=3), strip.border=list(lwd=3)),
         cex=1.4, scales=list(x=list(cex=1.7),y=list(cex=1.7)),xlab=list(label="Longitude",cex=2),
          ylab=list(label="Latitude",cex=2))

Thanks to @fdestch I was able to generate the following plot using:

latticeCombineGrid(mget(rep("pp", 24)), layout = c(3, 8))

following my comments on printing multiple plots with the same colorkey.

An issue that remains to be clarified:

1) How can one decide on the order of panels? That is, which row & column to place a particular plot just as in levelplot using index.cond .

Answer 1

First of all, you should probably make sure that the breaks in the points plot are identical with those defined in the first levelplot .

## raster plot with colorkey disabled
pr <- levelplot(s, margin = FALSE, at = seq(0, 1, 0.05), col.regions = col, 
                colorkey = FALSE, xlab = list("Longitude", col = "transparent"))

## points plot 
pp <- levelplot(z ~ x + y, panel = panel.levelplot.points, cex = 1.4, 
                contour = FALSE, margin = FALSE, col.regions = col, 
                colorkey = list(at = seq(0, 1, .05), width = .6, height = .6),
                xlab = "Longitude", ylab = "Latitude")

Please note the definition of a transparent xlab when creating the raster plot. This little workaround comes in quite handy when using downViewport later on to ensure that the actual plot boundaries of pr and pp overlap (feel free to run grid.rect() right after print(pr, newpage = FALSE) to see what I mean).

The actual plot arrangement can then easily be achieved by using viewports from the grid package.

library(grid)
library(lattice)

## initialize new grid device
grid.newpage()

## add raster plot
vp1 <- viewport(x = 0, y = 0, width = .5, height = 1, 
                just = c("left", "bottom"))

pushViewport(vp1)
print(pr, newpage = FALSE)

## add points plot
downViewport(trellis.vpname("page"))

vp2 <- viewport(x = 1, y = 0, width = .75, height = 1, 
                just = c("left", "bottom"))
pushViewport(vp2)
print(pp, newpage = FALSE)

Answer 2

Here is my solution using latticeExtra::c.trellis :

library(raster)
library(rasterVis)

s <- stack(replicate(2, raster(matrix(runif(100), 10))))
xy <- data.frame(coordinates(sampleRandom(s, 10, sp=TRUE)),
                 z1=runif(10), z2=runif(10))

## Define theme and breaks
myTheme <- BTCTheme()
my.at <- seq(0, 1, 0.05)

• Plot the Raster* object, using rasterVis::levelplot :

   p1 <- levelplot(s, margin=FALSE, at = my.at, par.settings = myTheme) 

• Plot the points, using lattice::levelplot :

   p2 <- levelplot(z1 ~ x + y, data = xy, at = my.at, panel = panel.levelplot.points, par.settings = myTheme) 

• Join them with latticeExtra::c.trellis :

   p3 <- c(p1, p2, layout = c(3, 1)) 

• Unfortunately, c.trellis does not assign the strip labels correctly, so you have to define them directly:

   update(p3, strip = strip.custom(factor.levels = c(names(s), "Points")))