ggplot2 geom_bar axis limits...x-axis limits and labels

Question

I already browsed a lot, but unfortunately I just find vague information. I want to display a sex ratio over length classes. To achieve that I did a stacked barplot with ggplot2 (geom_bar). This is the code:

Data <- data.frame(LCnew=c(30,30,31,31,32,32,33,33,34,34,35,35,36,36,37,37,38,38,39,39,40,40), 
                   sex=c(1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2))
ggplot(Data, aes(x=factor(LCnew), fill=factor(sex)))+geom_bar(position="fill") +  scale_x_discrete("Lengthclass [mm]") +  scale_y_continuous("Proportion of sexes") + scale_fill_manual(values=cols)

cols is just a simple vector with colours in it.

This is the plot so far:

My problem is that I am not able to change the axis text. I just want text below every fifth bar, otherwise they are overlapping. I tried it with the limits and breaks command, but this just gave me an empty graph.

scale_x_continuous("Standard Length [mm]",limits=c(30,85),breaks=c(30,35,40,45,50,55,60,65,70,75,80,85))

Any suggestions?

to be honest: I don't know how to add data...it's my first question here and I'm still struggeling. sorry for that :/ — kilewi
Sorry for being a bit overchallenged. My dataset has the same structure like this matrix: 'y <- matrix(c(30,30,31,31,32,32,33,33,34,34,35,35,36,36,37,37,38,38,39,39,40,40,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2),nrow=22, ncol=2) colnames(y) <- c("length","sex")' but when I want to plot it, it get an error message that ggplot does not know how to deal with data of class matrix. but at least it has the same structure like my data.... — kilewi

Jaap Jaap · Accepted Answer · 2015-10-21T16:18:41

If you want to prevent that the labels are overlapping, there are several strategies you can follow:

1) Define the breaks:

ggplot(y, aes(x=factor(length), fill=factor(sex))) +
  geom_bar(position="fill", width=0.7) +
  scale_x_discrete("Standard Length [mm]", breaks=c(300000,350000,400000)) +
  scale_y_continuous("Proportion of sexes", expand=c(0,0)) + 
  scale_fill_manual("Sex", values=c("blue","pink"), labels=c("Male","Female")) +
  theme_minimal()

which gives the following plot:

2) Change the angle of the labels:

ggplot(y, aes(x=factor(length), fill=factor(sex))) +
  geom_bar(position="fill", width=0.7) +
  scale_x_discrete("Lengthclass [mm]", expand=c(0,0)) +
  scale_y_continuous("Proportion of sexes", expand=c(0,0)) + 
  scale_fill_manual("Sex", values=c("blue","pink"), labels=c("Male","Female")) +
  theme_minimal() +
  theme(axis.text.x = element_text(angle=90, vjust = 0.5))

which gives:

3) Rotate the plot:

ggplot(y, aes(x=factor(length), fill=factor(sex))) +
  geom_bar(position="fill", width=0.7) +
  scale_x_discrete("Lengthclass [mm]", expand=c(0,0)) +
  scale_y_continuous("Proportion of sexes", expand=c(0,0)) + 
  scale_fill_manual("Sex", values=c("blue","pink"), labels=c("Male","Female")) +
  coord_flip() +
  theme_minimal()

which gives:

Used data:

y <- structure(list(length = c(300000, 300000, 310000, 310000, 320000, 320000, 330000, 330000, 340000, 340000, 350000, 350000, 360000, 360000, 370000, 370000, 380000, 380000, 390000, 390000, 400000, 400000, 300000, 310000, 330000, 340000, 360000, 380000, 390000), 
                    sex = c(1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 1, 2)), .Names = c("length", "sex"), row.names = c("1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12", "13", "14", "15", "16", "17", "18", "19", "20", "21", "22", "110", "41", "71", "101", "131", "171", "201"), class = "data.frame")

ggplot2 geom_bar axis limits...x-axis limits and labels

2 Answers