reducing the space between plotted points in plot( x, y) type=n

Question

I want to reduce the spacing between some plots that I made. I didn\'t get specific answers to my problem via the search facility.

All I want is to halve the horizontal

Answer 1

Aside from your main question, this is possibly the most convoluted plotting procedure I've ever seen. To simplify things, I would seriously consider collecting your data into a data.frame first like so:

dat <- setNames(data.frame(rbind(b,d,g,p)),c("value","low","high"))
dat
#   value    low   high
#b 12.142 12.076 12.208
#d 12.800 12.700 12.900
#g 12.100 12.000 12.200
#p 12.669 12.528 12.811

On to the main query - if you want to "push" the points together, you probably have a couple of options. Either make the plot itself smaller, or push the left and right margins in.

To push the margins in, set them with a call to ?par like:

# in order - margins for bottom,left,top,right
# for reference, the defaults are c(5.1,4.1,4.1,2.1)
par(mar=c(5.1,9,4.1,9))

Otherwise, just specify a smaller plotting window with your desired width and height which will compress the graph:

dev.new(width=5,height=4)

Your code could then be simplified greatly using the data.frame generated at the beginning of this post. E.g.:

# set some constants
  # nominal locations of points on x-axis
xpts <- 1:nrow(dat)
  # 95CI bar width
bar <- 0.05
  # colour scheme
palette(c("red","blue"))

# make the base plot
plot(xpts, dat$value, ylim=c(min(dat),max(dat)), 
     col=1:2, pch=19, cex=2, xaxt="n")

# add the axis back with proper labels
axis(1,at=xpts,labels=rownames(dat))

# add the 95% CI bars and lines
segments(xpts,dat$low,xpts,dat$high,col=1:2,lwd=2)
segments(xpts-bar,dat$low,xpts+bar,dat$low,col=1:2,lwd=2)
segments(xpts-bar,dat$high,xpts+bar,dat$high,col=1:2,lwd=2)

Which looks like the below, when using the margin squashing method: