Question

I am having problems getting segments of small lengths to appear in my plot.

Assuming the following sample data:

x=c(11,22,33,44,55)
y=c(15,23,33,45,57)
z=strptime(20120101:20120105,'%Y%m%d')

If I were to create segments out of this data my segment for the third record does not show up if I want square or butt line ends. It does show up if I allow my line ends to be round lend=0.

plot(z,x,type='n')
segments(as.numeric(z),x,as.numeric(z),y,lwd=5,lend=2)

If I try this:

segments(as.numeric(z),x,as.numeric(z),y,lwd=5,lend=0)

It shows a circle at 33. Is there a way to get at the very least a flat line that will appear at 33 (hopefully in base)?

I would have used my actual data which is also doing this when the range is small for instance 33.0005 to 33.0010, but that data is huge and I was hoping solving for when they are identical would also solve for small ranges.

ETA: If lwd=15 the circle looks even more ridiculous.

Maybe segments are not the right way to approach this?

This is for a candlestick chart, so these numbers would represent open and close. I also have high and low numbers which extend beyond this range and are drawn using lwd=1 under these segments.

Answer 1

Base graphics does supply rect. And in fact, it does what you want. Using your definitions above.

xdiff <- max(as.numeric(z)) - min(as.numeric(z))
segwidth <- xdiff/50

plot(z,x,type='n')
rect(z-segwidth/2, x, z+segwidth/2, y, col="black")