rasterVis - setting the bottom plots in the middle with levelplot

问题

I am using the awesome rasterVis to create a panel with maps that have the same extent (i.e. same spatial coverage) but that show different features (i.e. each with its own legend).

This is what it looks like so far:

library(raster)
library(rasterVis)
library(RColorBrewer)
library(gridExtra)

# make-up data
r <- raster(system.file("external/test.grd", package="raster"))
s <- stack(r, r*2, r*3, r*4, r*5)
names(s) <- paste0("Field ",seq(1,5))

# pre-allocate list
l <- vector("list", length=nlayers(s))

# define theme for plots
my.theme <- rasterTheme(region=brewer.pal(11,'RdYlGn'))

# loop over stack layers to fill list
for (n in (1:nlayers(s))){
  
  l[[n]] <- levelplot(s[[n]], margin=F, main=names(s[[n]]), par.settings=my.theme)
  
}

# plot combined maps
grid.arrange(l[[1]], l[[2]], l[[3]], l[[4]], l[[5]], ncol=3)

Note that the default positioning for the maps is:

a b c
d e

However, I would like to have a finer control on the positioning. Specifically, I would like to "center" the bottom two facets in order to distribute the void space more evenly on the sides of the plot.

In other words, the placement I am looking for would look like:

a b c
 d e

How can I achieve this? I looked up the documentation for (grid.arrange), but couldn't find any option the would solve my problem.

Thanks in advance for any hints.

回答1:

Here's an approach with cowplot::plot_grid inspired by this answer

library(cowplot)
top <- plot_grid(l[[1]], l[[2]], l[[3]],
                 ncol=3)
bottom <- plot_grid(NULL, l[[4]], NULL,  l[[5]], NULL,
                    ncol=6, rel_widths=c(0.12,0.34,0.12,0.34,0.06))
plot_grid(top, bottom,
          ncol=1, rel_heights=c(1,1))

You can modify the rel_widths in the bottom plot_grid call to get it just like you like.

回答2:

You can provide a layout with 6 columns and use NA for the blanks,

library(gridExtra)

p <- ggplot()

grid.arrange(grobs = list(p,p,p,p,p), 
             layout_matrix = rbind(c(1,1,2,2,3,3), c(NA,4,4,5,5,NA)))

来源：https://stackoverflow.com/questions/62730787/rastervis-setting-the-bottom-plots-in-the-middle-with-levelplot

标签

lattice

gridextra

levelplot

rastervis