On Mon, 2005-08-29 at 12:58 -0400, Doran, Harold wrote: > Dear list: > > I have some data for which I am generating a series of barplots for > percentages. One issue that I am dealing with is that I am trying to get > the legend to print in a fixed location for each chart generated by the > data. Because these charts are being created in a loop, with different > data, my code searches the data to identify the maximum value in the > data and then print the data values 5 points above the tallest bar. > > Now, in situations where the largest value is 100, I needed to create > the y-axis high enough to accommodate the legend w/o crowding up the > data or the bars. So, I have ylim =c(0,200) and then place the legend at > c(2,150). Visually, this places things exactly where I want them. But, > it seems silly to have a y-axis labeled as high as 200%. I'm certain > there is a smarter technique. Is it possible to place the legend at a > location higher than 100 to avoid the crowding of the bars and the data > and then also have the labels for the y-axis not print after the value > 100%? > > In looking at ?legend I didn't see an option that would address this. > Below is some code that you can use to create a similar chart. > > Thanks, > Harold > > > math.bar <- c(53,31,55,28,55,100) > apmxpmeet <- c(47, 50, 49, 50, 49, 46) > par(ps=10) > math.bar <- rbind(math.bar, apmxpmeet) > math.barplot <- barplot(math.bar, beside=T, col=c('blue','orange'), > names=c('Grade \n 3','Grade \n 4','Grade \n 5','Grade \n 6','Grade \n > 7','Grade \n 8'), > ylim=c(0,200), ylab="Percentage", xlab="Grade Level") > tot <- round(math.bar,digits=0) > graph.max <- max(math.bar, apmxpmeet, na.rm=T) > text(math.barplot, graph.max+5, tot, xpd = TRUE, col = c("blue", > "orange") ) > legend(2,150,legend=(c("Label A", "Average")), fill=c("blue","orange"))
Harold, A few thoughts: 1. Instead of fixing the y axis max value at 200, simply set ylim to c(0, max(math.bar * 1.2)) or a similar constant. In this case, you get an extra 20% above the max(y) value for the legend placement. 2. In the legend call, use: legend("topleft", legend=(c("Label A", "Average")), fill = c("blue","orange")) This will place the legend at the topleft of the plot region, rather than you having to calculate the x and y coords. If you want it moved in from the upper left hand corner, you can use the 'inset' argument as well, which moves the legend by a proportion of the plot region limits (0 - 1): legend("topleft", legend=(c("Label A", "Average")), fill = c("blue","orange"), inset = .1) 3. You can use barplot(..., yaxt = "n") to have the y axis not drawn and then use axis() to place the labels at locations of your choosing, which do not need to run the full length of the axis range: barplot(1:5, yaxt = "n", ylim = c(0, 10)) axis(2, at = 0:5) 4. You can place the legend outside the plot region, enabling you to keep the y axis range to <=100. This would need some tweaking, but the idea is the same: # Increase the size of the top margin par(mar = c(5, 4, 8, 2) + 0.1) # Draw a barplot barplot(1:5) # Disable clipping outside the plot region par(xpd = TRUE) # Now draw the legend, but move it up by 30% from the top left legend("topleft", legend = LETTERS[1:5], inset = c(0, -.3)) You could also place the legend to the right or left of the plot region if you prefer, adjusting the above accordingly. HTH, Marc Schwartz ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html