How to plot EKMA diagram using Rstudio

Question

I am new to R studio. In general, I know how to generate a plot based on ggplot commands. I am wondering if it is possible to generate an EKMA diagram to show relationships between NOx, VOC and O3 from my observations by using ggplot.

My input file contains 3 columns (i.e. VOC, NOx and O3) and 1900 rows/column.

Hourly NOx: 9.88 12.58 16.58 19.86 17.54 10.66 8.36 6.42 6.37 6.60 5.19 4.48 4.55 4.43 4.66 4.08 3.57 3.34 3.67

Hourly O3: 29.26 24.64 19.11 13.93 13.90 19.34 21.69 23.75 24.11 25.70 29.73 33.07 36.82 38.75 40.63 40.55 41.67 42.93 43.73

Hourly VOC: 119.57 245.59 253.63 259.13 275.98 277.01 269.21 253.86 239.78 234.09 224.97 225.47 221.39 217.65 217.38 215.43 214.73 215.44 218.37

The following EKMA diagram is the diagram that I would like to generate (please follow the link. I am not allowed to post a photo over here). VOC is x axis, NOx is y axis and curve lines are O3 levels. EKMA Diagram

[1]: https://i.sstatic.net/mih0B.gif

Any suggestions are welcome and appreciated.

Answer 1

As @tamtam has said, you would get a better answer if you provide your input data. That said, producing a plot of the type you want should be pretty straightforward. Here is proof-of-concept using bivariate Normal data. It should be easy to adapt to your specific use case and, once you have the basic presentation of the data, customising the axes, titles and annotations should simply be a matter of reading the online documentation and setting the options you need.

library(mvtnorm)
library(tidyverse)

# Generate the data
d <- expand_grid(
       x=seq(-3, 3, 0.1),
       y=seq(-3, 3, 0.1)
     )
d$z = dmvnorm(as.matrix(d))

# Define the reference lines
lines <- tibble(
           x=c(-2, -2, -2, 2, 2, 0), 
           y=c(-2, -2, -2, 0, 2, 2), 
           id=c("A", "B", "C", "A", "B", "C")
         )

# Create the graph
d %>% 
  ggplot() +
    geom_contour(aes(x=x, y=y, z=z)) +
    geom_line(data=lines, aes(x=x, y=y, colour=id))