High level plot commands open a graphics device. High level plot elements add objects. R plot parameters ensure actual control over the graphics device.
R Plot Parameters
All high level plotting functions have arguments which can be used to customize the plot. barplot(), for example, has arguments to control bar width, styles, etc. High level functions also take the optional “three dots” argument, which allows for argument sharing. The most common arguments shared are low level graph parameters from the par() function.
The tables below define graphical parameters by type. The most commonly used are highlighted with †. The example notation c denotes one character for input; i, j, m, and n are integers; L is a logical value; x requires a numeric data object as input:
Layout Parameters
[table id=26 /]
Plot Formatting
[table id=27 /]
Margins
[table id=29 /]
Plot Area
[table id=30 /]
Axes
[table id=31 /]
Text and Symbols
[table id=32 /]
Plot Symbols
Plot symbols are displayed below with their pch=n code:
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 |
# Plot Symbols # Define symbol list sym.seq <- 0:29 sym.list <- as.list(sym.seq) sym.list[27:30] <- as.list(c("+", "o", "#", "*")) # Configure graphical device n.sym <- length(sym.seq) n.row <- floor(sqrt(n.sym)) x.seq <- sym.seq %/% n.row y.seq <- 3 + (n.row-1) - sym.seq %% n.row x.coord <- range(x.seq) + c(-0.5, 0.5) y.coord <- range(y.seq) + c(-0.5, 0.5) # Create plot skeleton plot(x.coord, y.coord, type = "n", axes = FALSE, xlab = "", ylab = "", main = "Plot Symbols") # Add plot elements abline(v=x.seq, h=y.seq, col = "gray90", lty = "dotted") for(i in 1:n.sym){ sym <- sym.list[[i]] points(x.seq[i], y.seq[i], pch = sym, col = "darkgreen", bg = "gold", cex = 3) text(x.seq[i] - 0.4, y.seq[i], labels = sym, col = "red") } |
Anatomy of a Plot
A figure consists of a plot region surrounded by 4 margins:
Click to enlarge
The fundamental anatomy fields are critical to managing layout parameters. For example, the following layout diagram outlines parameters for customizing a 3×2 multi-figure graphic where mfg=c(3,2) with outer margin parameters:
