向ggplot2添加错误栏

Question

I have made a graph using ggplot from data I transformed into means with code:

I would like to know if there is anyway I can add error bars to this graph. I know I have to transform the data to have more summaries but not sure how to proceed. Tried to do it seperately for each column but could'nt make a graph from it. like this:

Temperature <- ddply(shlf, c("Location"), summarise,
                       N = length(temp),
                       mean.temp = mean(temp),
                       sd = sd(temp),
                       se = sd / sqrt(N))

Any help is appreciated.

Answer 1

You are almost there. This is based on se as provided in Temperature data:

means$upper = Temperature$mean.temp + Temperature$se
means$lower = Temperature$mean.temp - Temperature$se

ggplot(means, aes(x = temp,
                  y = Triconia,
                  color = Location)) +
   geom_point(size = 5.0) +
   geom_errorbarh(aes(xmin = upper, xmax = lower))

Errorbar as a separate geom comes in distinct flavors: geom_errorbar is vertical and geom_errorbarh is horizontal; there are also things like geom_crossbar , geom_pointrange and the like. See ?geom_errorbar for help and some examples on all of them.