Thorn Plot, for visualising head winds, final version

Continuing the short series on plotting headwinds, perhaps you prefer the 'thorn plot' version, in which the relative frequency of wind from a particular direction is represented both by transparency of colour and also by the width of the triangle.

For this version, I finally remembered to normalise the number of observations between locations. There are more records for some airports than others, but this is irrelevant for the graph, so I rescale.

Final daisy plot for visualising head wind when cycling.

Got there in the end. I know he guidance is that colour is not the best way to show variation, but this 'daisy plot' works for me, and is less untidy than the 'thorn' variation.

The curved line comes from those explicitly drawn by ggplot in the geom_poly statement, so repeating the start point of the poly gave me a balanced curve on both sides (which gives a clue as to how to get straight lines, but I'm sticking with this version).

Quite a lot of ggplot in the end:

ggplot(y8p , aes(x, y, group = windHead, alpha = numObs)) + 

  scale_alpha(range = c(0.3, 1), breaks = seq(0, 24000, by = 4000)) + 

  geom_polygon(fill = "blue") +

  xlab("Angle = Wind heading (deg) ") + 

  ylab("Mean wind speed (km/h)") +

  labs(alpha = "Observations") +

  coord_polar(start = -pi/8) + 

  scale_y_reverse(limits = c(maxKMH, 0)) + 

  scale_x_continuous(limits = c(-22.5,337.5), breaks = NULL) +

  geom_label(aes(x=0, y = maxKMH, label = station), colour = "black",

             show.legend = FALSE) +

  #theme(legend.position = c(1,0), legend.justification = c(1,0)) + 

  theme(strip.background = element_blank(),

        strip.text.x = element_blank()) +

  facet_wrap( ~ station)

For which, the y8p data looks like this. Note that I've created 4 lines for each real line of data - and x and y give the 4 points used in the polygon for each real point of data.

  station windHead   windKPH numObs     x         y

    <chr>   <fctr>     <dbl>  <int> <dbl>     <dbl>

1    EBBR        0  9.167982   7190   0.0  9.167982

2    EBBR        0  9.167982   7190  22.5  0.000000

3    EBBR        0  9.167982   7190 -22.5  0.000000

4    EBBR        0  9.167982   7190   0.0  9.167982

5    EBBR       45 10.177946   7358  45.0 10.177946

6    EBBR       45 10.177946   7358  67.5  0.000000