ggplot2 offset scatterplot points

Question

I have two sets of points with error bars. I would like to offset the second so it\'s displayed slightly down from the first set, so that it doesn\'t obscure the original.<

Answer 1

Using Richie's reorganization of your data, this is also possible purely within ggplot, without having to mess with the axis:

dodge <- position_dodge(width=0.5)  
p <- ggplot(dfr,aes(x=y,y=x,colour=type)) + 
        geom_point(aes(shape=type),position=dodge) +
        geom_errorbar(aes(ymax=upper,ymin=lower),position = dodge) + 
        scale_colour_manual(values = c('gray','black')) +
        scale_shape_manual(values = c(8,19)) +
        coord_flip() + 
        opts(legend.position="none")

which gives me this plot:

Note: Since version 0.9.2 opts has been replaced by theme:

+ theme(legend.position = "none")