GGPlot2 Boxplot only shows flat lines

user_3146687 0
Viewed 23032

I have been working on this for hours, cant seem to get this right. The boxplot only gives me flat vertical lines, its driving me crazy. I get the same input with or without factor function

ggplot(df2,aes(x = factor(Location),y=Final.Result)) + geom_boxplot()

Solved! there are some data values such as "< 0.005" which R picks up as string and converts everything to factor.

boxplot ggplot2 r
3 Answers

This answer is only related to the title of the question, but this question ranks top if I google "ggplot2 boxplot only lines" and there was no other helpful search result on that search term, so I feel it fits here well:

Boxplots only work if you specify the quantity as y aestetic.

EDIT: Since ggplot 3.3.0, there is the orientation= parameter that allows to change the orientation. See the ggplot NEWS on this

Compare

 ggplot(mtcars, aes(x = factor(cyl), y = disp)) + geom_boxplot()

sample boxplot with x = quantity and y = grouping

which gives correct boxplots with

 ggplot(mtcars, aes(y = factor(cyl), x = disp)) + geom_boxplot()

boxplot with incorrect aesthetic setting

which gives only lines instead of box plots.

To obtain horizontal box plots, use coord_flip():

 ggplot(mtcars, aes(x = factor(cyl), y = disp)) + 
   geom_boxplot() + coord_flip()

vertical boxplot

user_30824720

Another reason you get flat lines instead of boxes is that you summarized the numeric values in your table (eg calculating mean, median, etc.) and now boxplot() sees only a single value.

user_45894020
Related