Dear Stackoverflow users,
I would like to draw a grouped barplot with three independent variables with error bars. I based my graph on an example on Stacked Overflow (stacked bars within grouped bars), using ggplot with geom_bar. When I add the geom_errorbar according to examples of the help pages, I get the following error:
Error in if (empty(data)) { : missing value where TRUE/FALSE needed
This is the script I use:
treatment<-rep(c(rep(c(1),8),rep(c(2),8)),2)
origin<-rep(c("A","B"),16)
time<-c(rep(c(5),16),rep(c(10),16))
sulfide<-c(0,10,5,8,9,6,16,18,20,25,50,46,17,58,39,43,20,25,50,46,17,58,39,43,100,120,103,104,150,160,200,180)
Reed<-data.frame(treatment,origin,time,sulfide)
# specify factor types
Reed$treatment<-as.factor(Reed$treatment)
Reed$origin<-as.character(Reed$origin)
Reed$time<-as.factor(Reed$time)
library(ggplot2)
library(scales)
#draw plot
ggplot() +geom_bar(data=Reed, aes(y = sulfide, x = treatment, fill=origin), stat="identity",position="dodge") +theme_bw() + facet_grid( ~ time)+xlab("treatment") +ylab("Sulfide")+ggtitle("Time)")
This is how I added error bars:
ErrorBars <- function(x, y, upper, lower=upper, length=0.03,...{if(length(x) != length(y) | length(y) !=length(lower) | length(lower) != length(upper))stop("vectors must be same length")arrows(x,y+upper, x, y-lower, angle=90, code=3, length=length, ...)}#function for errorbars
SE<- function(x) sqrt(var(x,na.rm=TRUE)/length(na.omit(x))) #function for SE
Reed$trt<- paste(Reed$treatment,Reed$origin,sep="")#combine treatment and origin to a column
mean_Reed<-data.frame(tapply(Reed$sulfide,list(Reed$trt,Reed$time),mean,na.rm=TRUE)) #mean
SE_Reed<-data.frame(tapply(Reed$sulfide,list(Reed$trt, Reed$time),SE)) # SE
limits <- aes(ymax = mean_Reed + SE_Reed, ymin=mean_Reed - SE_Reed)# Define the top and bottom of the errorbars
#plot with error bars:
ggplot() +geom_bar(data=Reed, aes(y = sulfide, x = treatment, fill=origin), stat="identity",position="dodge") +theme_bw() + facet_grid( ~ time)+xlab("treatment") +ylab("Sulfide")+ggtitle("Time)"+ geom_errorbar(limits, width=.2,position="dodge")
I really can't find what I'm doing wrong. I hope you can help me:)