Reading in R a Seasonal Polar Season Plot

Question

I just want to know that how we can read the amount being measured in a Polar Seasonal Plot.

REPREX:

library(tidyverse)  

library(fpp2)       

ggseasonplot(a10, polar = T)

 In the above plot, how to get the amount (in millions) that was sold in July 2008? 

Answer 1

I think the 10 and 20 are showing distances from the core horizontal line (Oct-May), and if you assume horizontal lines extending from the 10 and the 20, those lines up as tangent to the faint grid lines. Accidentally, the 10 is more adjacent to the center than the 20, which is implying that either the scale isn't linear or it doesn't start at 0 in the center.

I've interpreted the plot here with the straight lines and circling the tangents.

You can also use the annotate or geom_text to add tags directly to the plot and use the theme() to make the grid lines a little more understandable.

If you are a beginner and want to know more about R then do check out the R programming tutorial.