# Positioning charts with fig and fin

R offers several ways to spatially orient multiple graphs in a single graphing space. The `layout()` function and `mfrow`/`mfcol` parameter settings are adequate solutions for many tasks and allow the graphing space to be broken up into tabular or matrix-based arrangements. For more fine grained manipulation, the `fig` and `fin` parameter settings are available. This article illustrates the capabilities and use of `fig` and `fin`.

First we’ll create some simulation data to work with:

` # create data sim.data `

The code above results in a matrix object with eight rows and three columns.

The `fig` and `fin` parameters affect the same graphing elements via different units. The fig parameter takes normalized device coordinates (NDC) and fin takes dimensions in inches of the device region. Because the `fig` units are generally more user friendly, I will use it in the examples below; however, selecting equivalent dimensions using the `fin` would have an identical effect. Similar to other functions that use NDC to define graphing space, `fig` takes a four item vector wherein positions one and three define, in percentages of the device region, the starting points of the x and y axes, respectively, while positions two and four define the end points. The default `fig` setting is `(0, 1, 0, 1)` and uses the entire device space. The default `fig` setting is `(0, 1, 0, 1)` and uses the entire device space. The graph below illustrates the default settings of `fig`.

` # graph cases by first column using default fig # settings of 0 1 0 1 (the full device width and height) par(mar=c(2, 2, 1, 1), new = FALSE, cex.axis = .6, mgp = c(0, 0, 0)) `

` #open plot plot(c(0,100), c(-1,1), type = "n", ylab = "", yaxt = "n", xlab = "") points(sim.data[,1], replicate(8, 0), pch = 19, col = 1:8, cex = 1.5) # add center reference line abline(0,0) legend("bottomright", fill = c(1:8), legend = c(1:8), ncol = 4) `

To make the horizontal dimensions of the graph smaller or to move the graph left or right, adjust the starting and ending x coordinates, given by the first and second positions of the `fig` value vector. To make the vertical dimensions of the graph smaller or to move the graph up or down, adjust the staring and ending y coordinates given in the third and fourth positions as below.

` # decrease horizontal span par(fig=c(0, 1, .2, .8)) `

` #open plot plot(c(0,100), c(-1,1), type = "n", ylab = "", yaxt = "n", xlab = "") points(sim.data[,1], replicate(8, 0), pch = 19, col = 1:8, cex = 1.5) # add center reference line abline(0,0) legend("bottomright", fill = c(1:8), legend = c(1:8), ncol = 4) `

It is possible to resize and move a single graph to any spatial orientation on the graphing device using the approach above (includes an additional edit using abline). Additionally, you can also use this method to add multiple graphs of various sizes to a single device:

` # place graph one in the bottom left par(fig=c(0, .25, 0, .25), mar=c(2,.5,1,.5), mgp=c(0, 1, 0)) `

` #open plot plot(c(0,100), c(-1,1), type = "n", ylab = "", yaxt = "n", xlab = "") points(sim.data[,1], replicate(8, 0), pch = 19, col = 1:8) # add center reference line abline(0,0) `

` # place graph two in the top right # set graphing parameters for next plot and set new parameter to TRUE par(fig=c(.75, 1, .75, 1), new = TRUE) `

` #open plot plot(c(0,100), c(-1,1), type = "n", ylab = "", yaxt = "n", xlab = "") points(sim.data[,2], replicate(8, 0), pch = 19, col = 1:8) # add center reference line abline(0,0) `

` # place main graph in the center # set graphing parameters for next plot and set new parameter to TRUE par(fig=c(.25, .75, .25, .75), new = TRUE) `

` #open plot plot(c(0,100), c(-1,1), type = "n", ylab = "", yaxt = "n", xlab = "") points(sim.data[,3], replicate(8, 0), pch = 19, col = 1:8, cex = 1.5) # add center reference line abline(0,0) legend("bottomright", fill = c(1:8), legend = c(1:8), ncol = 4) `

For simplicity I have mostly avoided labels and titles in these graphs; however they can be added and manipulated as they would be without the use of `fig` or `fin`.

This article was one of several this blog has done on graphics and visualization; you may also be interested in:

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Positioning charts with fig and fin
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