What does the height of bars in the two bar chats with different “position” represents?

Question

In the following syntax, the height of the bars represents the count of each group in this variable "color":

ggplot(diamonds, aes(color, fill = cut)) +geom_bar()

But I am not able to understand what the following code is doing:

ggplot(diamonds, aes(color, fill = cut)) + geom_bar(alpha=0.5, position = "identity")

Can you please explain what position and alpha are doing?

Answer 1

Say for instance, in R programming when you plot any graph using ggplot2 and inside the ggplot function you are having position='dodge' in that it helps to place the multiple bars for different cuts, separated by color and it doesn't layer all the cut bars on top of each other.

ggplot(diamonds, aes(color, fill = cut)) + geom_bar(alpha=0.5, position = "dodge")

 

ggplot(diamonds, aes(color, fill = cut)) +  geom_bar(alpha=0.5, position = "identity")

Note: The colors get distorted because the 'Fair' cut is in front.