CODEWITHSUNDEEP
rggplot2jitter
Hjalte
Hjalte

Reputation: 396

ggplot - From numerical to categorical x-

I need to make a plot of three mean values +- SE, and the add some additional points to this plot. The y-axis is numerical and the x-axis should be categorical. Some of the additional points have the same y-value within the same category, so to get the point offset, so they did not cover each other, I changed my categories to values 5,10,15, and then gave the two points overlapping for 5 the x-values of 4.9 and 5.1. This works perfect - but now I need to have the categories show on the x-axis.

This is my original data:

Island;Armean;SE;TLR3;TLR4
ST;4,166666667;0,477;1;1
FG;3,666666667;0,715;3;3
SN;1,666666667;0,333;3;2

TLR3 and TLR4 hold the values for the additional points I want to plot.

qplot(df$Island, df$Armean) + geom_errorbar(aes(x=df$Island, ymin=df$Armean-df$SE, ymax = df$Armean+df$SE), width = 0.25) + geom_point(aes(y=df$TLR3), color ="red") + geom_point(aes(y=df$TLR4), color ="blue") + theme_bw()

The above gives me the plot I need, but except I need to offset the points on 3 for FG and 1 for ST.

enter image description here

I changed my dataset to this:

Island;Armean;SE;TLR3;TLR4
5;4,166666667;0,477;NA;NA
10;3,666666667;0,715;NA;NA
15;1,666666667;0,333;3;2
4,92;NA;NA;1;NA
5,08;NA;NA;NA;1
9,92;NA;NA;3;NA
10,08;NA;NA;NA;3

Which offsets the points perfectly, but I am not sure how to get the old categories back on the x-axis?

I could use jitter instead of the above, but I wish the points to have the same distance to the center line, and only the point that overlap to be offset.

enter image description here

Upvotes: 1

Views: 2115

Answers (1)

Mike H.
Mike H.

Reputation: 14370

EDIT: Per @Gregor's comment below, changed qplot to ggplot

Should be simple enough to get your old categories on the X-Axis. Try this:

ggplot(data=df,aes(Island,Armean)) +
  geom_errorbar(aes(x=Island, ymin=Armean-SE, ymax = Armean+SE), width = 0.25) + 
  geom_point(aes(y=TLR3), color ="red") + 
  geom_point(aes(y=TLR4), color ="blue") + theme_bw() + 
  scale_x_continuous(breaks=seq(from=5,to=15, by = 5), labels=c("FG","SN","ST"))

Which gives the output of:

enter image description here

If you don't want to add in the labels manually you can do this by adding in another column to your dataframe that contains the levels you want. See:

df <- read.csv(textConnection("Island;Armean;SE;TLR3;TLR4;Island.group
5;4,166666667;0,477;NA;NA;ST
10;3,666666667;0,715;NA;NA;FG
15;1,666666667;0,333;3;2;SN
4,92;NA;NA;1;NA;ST
5,08;NA;NA;NA;1;ST
9,92;NA;NA;3;NA;FG
10,08;NA;NA;NA;3;FG"),header=TRUE,dec=",",sep=";")


 ggplot(data=df,aes(Island,Armean)) +
  geom_errorbar(aes(x=Island, ymin=Armean-SE, ymax = Armean+SE), width = 0.25) + 
  geom_point(aes(y=TLR3), color ="red") + 
  geom_point(aes(y=TLR4), color ="blue") + theme_bw() + 
  scale_x_continuous(breaks=seq(from=5,to=15, by = 5), labels=levels(df$Island.group))

Which gives the same exact output:

enter image description here

Upvotes: 2

Related Questions