ggplot2 Version of Figures in “Lattice: Multivariate Data Visualization with R” (Part 9)

This is the 9th post in a series attempting to recreate the figures in Lattice: Multivariate Data Visualization with R (R code available here) with ggplot2.

Previous parts in this series: Part 1, Part 2, Part 3, Part 4, Part 5, Part 6, Part 7, Part 8.

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Chapter 9 – Labels and Legends

Topics covered:

• Labels (main, sub, xlab, ylab)
• Legends, color keys
• Legends in grouped displays; auto.key
• Dropping unused levels of grouping variable
• Page annotation

Figure 9.1

> library(lattice) > library(ggplot2)

> data(Cars93, package = "MASS")

lattice

> sup.sym <- Rows(trellis.par.get("superpose.symbol"), + 1:5)

> pl <- xyplot(Price ~ EngineSize | reorder(AirBags, Price), + data = Cars93, groups = Cylinders, subset = Cylinders != + "rotary", scales = list(y = list(log = 2, tick.number = 3)), + xlab = "Engine Size (litres)", ylab = "Average Price (1000 USD)", + key = list(text = list(levels(Cars93$Cylinders)[1:5]), + points = sup.sym, space = "right")) > print(pl)

ggplot2

> Cars93$AirBags <- with(Cars93, reorder(AirBags, Price))

> pg <- ggplot(Cars93, aes(EngineSize, Price, colour = factor(Cylinders))) + + geom_point(subset = .(Cylinders != "rotary")) + facet_grid(~AirBags) + + xlab("Engine Size (litres)") + ylab("Average Price (1000 USD)") + + scale_y_log2() > print(pg)

Figure 9.2

lattice

> my.pch <- c(21:25, 20) > my.fill <- c("transparent", "grey", "black")

> pl <- with(Cars93, xyplot(Price ~ EngineSize, scales = list(y = list(log = 2, + tick.number = 3)), panel = function(x, y, ..., subscripts) { + pch <- my.pch[Cylinders[subscripts]] + fill <- my.fill[AirBags[subscripts]] + panel.xyplot(x, y, pch = pch, fill = fill, col = "black") + }, key = list(space = "right", adj = 1, text = list(levels(Cylinders)), + points = list(pch = my.pch), text = list(levels(AirBags)), + points = list(pch = 21, fill = my.fill), rep = FALSE))) > print(pl)

ggplot2

> pg <- ggplot(Cars93, aes(EngineSize, Price, shape = factor(Cylinders), + colour = factor(AirBags))) + geom_point() + scale_y_log2() > print(pg)

Figure 9.3

lattice

> library(latticeExtra) > hc1 <- hclust(dist(USArrests, method = "canberra")) > hc1 <- as.dendrogram(hc1) > ord.hc1 <- order.dendrogram(hc1) > hc2 <- reorder(hc1, state.region[ord.hc1]) > ord.hc2 <- order.dendrogram(hc2) > region.colors <- trellis.par.get("superpose.polygon")$col

> pl <- levelplot(t(scale(USArrests))[, ord.hc2], scales = list(x = list(rot = 90)), + colorkey = FALSE, legend = list(right = list(fun = dendrogramGrob, + args = list(x = hc2, ord = ord.hc2, side = "right", + size = 10, size.add = 0.5, add = list(rect = list(col = "transparent", + fill = region.colors[state.region])), + type = "rectangle")))) > print(pl)

ggplot2

> USArrests2 <- melt(t(scale(USArrests))) > USArrests2$X2 <- factor(USArrests2$X2, levels = state.name[ord.hc2])

> pg <- ggplot(USArrests2, aes(X1, X2, fill = value)) + + geom_tile() + opts(axis.text.x = theme_text(angle = 90, + hjust = 1, colour = "grey50")) + opts(aspect.ratio = 50/5) > print(pg)

Note	ggplot2 does not support the inclusion of dendrograms in the legend.