CODEWITHSUNDEEP
rggplot2radar-chart
Mariette Pretorius
Mariette Pretorius

Reputation: 21

how to place Y-axis values within radar chart

I have used the following example for my question: http://www.cmap.polytechnique.fr/~lepennec/R/Radar/RadarAndParallelPlots.html

mtcarsscaled <- as.data.frame(lapply(mtcars, ggplot2:::rescale01))
mtcarsscaled$model <- rownames(mtcars)
mtcarsmelted <- reshape2::melt(mtcarsscaled)

coord_radar <- function (theta = "x", start = 0, direction = 1) 
{
  theta <- match.arg(theta, c("x", "y"))
  r <- if (theta == "x") 
    "y"
  else "x"
  ggproto("CordRadar", CoordPolar, theta = theta, r = r, start = start, 
          direction = sign(direction),
          is_linear = function(coord) TRUE)
}

plot <- ggplot(mtcarsmelted, aes(x = variable, y = value)) +
  geom_polygon(aes(group = model, color = model), fill = NA, size = 2, show.legend = FALSE) +
  geom_line(aes(group = model, color = model), size = 2) +
  theme_bw()+
  theme(axis.text.x = element_text(colour="black",size=10), axis.text.y=element_text(size=14))+
  xlab("") + ylab("") +
  guides(color = guide_legend(ncol=2)) +
  coord_radar()

print(plot)

enter image description here

How do I move the values of the y-axis onto the radar plot so that they align with the major y-axis grid lines and get rid of the black box surrounding the plot?

Upvotes: 2

Views: 1631

Answers (1)

Z.Lin
Z.Lin

Reputation: 29095

You can add the y-axis values as annotated text, and remove the black box by changing the panel.border parameter in theme(...).

ggplot(mtcarsmelted, aes(x = variable, y = value)) +
  geom_polygon(aes(group = model, color = model), 
               fill = NA, size = 2, show.legend = FALSE) +
  geom_line(aes(group = model, color = model), size = 2) +
  xlab("") + ylab("") +
  guides(color = guide_legend(ncol = 2)) +
  coord_radar() +
  theme_bw()+

  # annotate
  annotate("text", x = 0, 
           y = seq(0, 1, 0.25), 
           label = seq(0, 1, 0.25)) +

  # remove original y-axis text / ticks & black border
  theme(axis.text.x = element_text(colour="black", size=10), 
        axis.text.y = element_blank(),
        axis.ticks.y = element_blank(),
        panel.border = element_blank())

plot

Side note: There are too many models in the same chart for this to be easily readable. If you are doing this for practice, that's fine. But if you intend to use it for communicating with others, you may wish to facet the plot so that only a few models are shown in each plot, or choose a different colour scheme that emphasizes only a few models of interest.

Upvotes: 3

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