I've found an issue when setting pos = n when I use the axes command for creating charts in R. When the y-axis range is -6 to -1, it all works perfectly, but when my range is for example -5 to -2 the axes won't meet at the specified position; the y-axis omits the -5 label and tick mark.
The code for one of my charts is as follows:
x <- c(3179047.6, 1956470.4, 609295.9, 136037.6)
y <- c(-4.758698, -4.227640, -4.019197, -2.653719)
model_fit <- lm(y~x)
par(mar=c(2.1, 2.1, 2.5, 1.1)) # I want to reduce the white space around the margins
plot(x, y, axes = FALSE, xlab = NULL, ylab = NULL, # I set the axes manually afterwards
ylim = c(c(min(0, y)), ceiling(max(y))),
xlim = c(0, 1000000*ceiling(max(x)/1000000)))
lines(x4, predict(model_fit), lty = 2, col = "red")
mtext(side = 1, line = 1.1, expression(paste(epsilon^"2")), cex = 0.7) # Greek symbol squared, title repositioned, font size lowered.
mtext(side = 2, line = 0, "Y-axis Title\n(units)", cex = 0.7) # font size lowered
mtext(side = 3, line = -0.5, "Main\nTitle",
cex = 0.8, font = 2)
axis(1, seq(0, 1000000*ceiling(max(x)/1000000), 1000000),
labels = seq(0, 1000000*ceiling(max(x)/1000000), 1000000),tck = -0.02, cex.axis = 0.6, padj = -3, pos = floor(min(y4)))
axis(2, seq(floor(min(y)), ceiling(max(y)), 1),
labels = seq(floor(min(y)), ceiling(max(y)), 1), tck = -0.02, cex.axis = 0.6, padj = 2, pos = 0)
par(mar=c(5.1, 4.1, 4.1, 2.1)) # Resetting the default margin sizes
For the axis() commands I've first set the range by seq(0, 1000000*ceiling(max(x)/1000000), 1000000), and then I repeated the command by setting labels = seq(0, 1000000*ceiling(max(x)/1000000), 1000000) to manually force the code to return the tick marks and labels at the correct position.
Then for the x-axis (axis 1), I set the position where it meets the y-axis (axis 2) at the minimum value of the y axis range by setting pos = floor(min(y4). The issue is for the chart produced by the above code, instead of having the y-axis extend down to meet the x-axis, there's a space and no tick or label for the -5 point.
This only happens when the range is between -2 and -5, for my chart where the range is -1 to -6, the two axes meet.
Is there some underlying code in the axis command I need to override?
