Stacked bar plot without y-axis values adding together (ggplot2)

Question

Trying to create a stacked bar plot with depth (in meters) on the y-axis and different categories on the x-axis and then filled with abundance values. However, ggplot2 keeps summing all the depth values (a+b+c) so that the y-axis isn't correct.

I know I need to specify geom_bar(stat = "identity"), but this seems to mess with the y-axis since all of the groups have the same values, but differing abundances.

##Data: 
Phylum  Depth   Abundance
Cnidaria    110 6
Cnidaria    90  12
Cnidaria    70  1
Cnidaria    50  4
Cnidaria    30  3
Cnidaria    20  1
Cnidaria    120 13
Cnidaria    80  3
Cnidaria    60  12
Arthropada  110 105
Arthropada  90  493
Arthropada  70  23
Arthropada  50  3
Arthropada  30  10
Arthropada  20  42
Arthropada  120 57
Arthropada  80  3
Arthropada  60  7

##Current plot: 
ggplot(data = data, aes(x = Phylum, y = Depth, fill = Abundance)) +
  geom_bar(stat = "identity")

The current plot outputs the data with the y-axis summed to 600 m when the highest value should only be 120 m.

Welcome to SO! When you place a question try to add a minimum content: input sample, expected output sample, what did you try, research and where are you stuck. What did you try? Not showing any effort... — David García Bodego
Based on your description, stacking bars by Phylum category isn't what you want. Are you able to include a sketch of what you expect the result to be? — Z.Lin

albeit2 albeit2 · Accepted Answer · 2019-10-30T04:23:22

Good thing is I do not think it is you code that is giving you trouble. Instead, I think you may want to consider an alternative way of displaying your data.

data = data.frame("Phylum" = c("Cnidaria", "Cnidaria", "Cnidaria", "Cnidaria","Cnidaria", "Cnidaria", "Cnidaria", "Cnidaria", "Cnidaria", "Arthropada", "Arthropada", "Arthropada", "Arthropada", "Arthropada", "Arthropada", "Arthropada", "Arthropada", "Arthropada"), "Depth" = c(110, 90, 70, 50, 30, 21, 120, 80, 60, 110, 90, 70, 50, 30, 20, 120, 80, 60), "Abundance" = c(6, 12, 1, 4, 3, 1, 13, 3, 12, 105, 493, 23, 3, 10, 42, 57, 3, 7))

The reason why it looks like the y-axis is adjusted is because the values are basically the same, which is shown by the averages of the categories:

aggregate(.~Phylum, data, mean)

      Phylum    Depth Abundance
1 Arthropada 70.00000 82.555556
2   Cnidaria 70.11111  6.111111

When you switch Depth and Abundance you get a plot more similar to what you are expecting:

p = ggplot(data = data, aes(x = Phylum, y = Abundance, fill = Depth))
p+geom_bar(stat = "identity")

You may want to consider different plots. For example, you may get better information by using Abundance and Depth for your x or y-axis and then filling in with the Phylum category.

Stacked bar plot without y-axis values adding together (ggplot2)

1 Answers