Add bar plot to heat map in ggplot2-CodePudding

I have the following dataset (the outpur is generated with dput):

    structure(list(Var1 = structure(c(1L, 1L, 2L, 1L, 2L, 3L, 1L, 
    2L, 3L, 4L, 1L, 2L, 3L, 4L, 5L, 1L, 2L, 3L, 4L, 5L, 6L, 1L, 2L, 
    3L, 4L, 5L, 6L, 7L, 1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 1L, 2L, 3L, 
    4L, 5L, 6L, 7L, 8L, 9L, 1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L, 10L, 
    1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L, 10L, 11L, 1L, 2L, 3L, 4L, 
    5L, 6L, 7L, 8L, 9L, 10L, 11L, 12L, 1L, 2L, 3L, 4L, 5L, 6L, 7L, 
    8L, 9L, 10L, 11L, 12L, 13L), levels = c("X0", "X1", "X2", "X3", 
    "X4", "X5", "X6", "X7", "X8", "maxd", "lag", "tas", "mean"), class = "factor"), 
        Var2 = c("X0", "X1", "X1", "X2", "X2", "X2", "X3", "X3", 
        "X3", "X3", "X4", "X4", "X4", "X4", "X4", "X5", "X5", "X5", 
        "X5", "X5", "X5", "X6", "X6", "X6", "X6", "X6", "X6", "X6", 
        "X7", "X7", "X7", "X7", "X7", "X7", "X7", "X7", "X8", "X8", 
        "X8", "X8", "X8", "X8", "X8", "X8", "X8", "maxd", "maxd", 
        "maxd", "maxd", "maxd", "maxd", "maxd", "maxd", "maxd", "maxd", 
        "lag", "lag", "lag", "lag", "lag", "lag", "lag", "lag", "lag", 
        "lag", "lag", "tas", "tas", "tas", "tas", "tas", "tas", "tas", 
        "tas", "tas", "tas", "tas", "tas", "mean", "mean", "mean", 
        "mean", "mean", "mean", "mean", "mean", "mean", "mean", "mean", 
        "mean", "mean"), value = c(1, 0, 1, 0, 0, 1, 0, 0, 0, 1, 
        0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 
        0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, -0.369, -0.068, 
        -0.263, -0.173, 0.042, -0.146, 0.077, 0.053, 0.09, 1, -0.15, 
        0.021, -0.124, -0.086, -0.011, 0.008, 0.043, 0.005, 0.068, 
        0.677, 1, -0.03, -0.149, 0.04, 0.019, 0.078, 0.06, 0.003, 
        -0.022, 0.089, 0.283, 0.247, 1, -0.101, -0.274, -0.176, -0.033, 
        0.08, 0.009, 0.081, 0.062, 0.154, 0.509, 0.49, 0.394, 1), 
        vif = c(1.60070614254443, 1.11225298408558, 1.11225298408558, 
        1.24667893632764, 1.24667893632764, 1.24667893632764, 1.13718634714263, 
        1.13718634714263, 1.13718634714263, 1.13718634714263, 1.06477651305619, 
        1.06477651305619, 1.06477651305619, 1.06477651305619, 1.06477651305619, 
        1.15665232275605, 1.15665232275605, 1.15665232275605, 1.15665232275605, 
        1.15665232275605, 1.15665232275605, 1.04455882370308, 1.04455882370308, 
        1.04455882370308, 1.04455882370308, 1.04455882370308, 1.04455882370308, 
        1.04455882370308, 1.0752045744496, 1.0752045744496, 1.0752045744496, 
        1.0752045744496, 1.0752045744496, 1.0752045744496, 1.0752045744496, 
        1.0752045744496, 1.07921364011364, 1.07921364011364, 1.07921364011364, 
        1.07921364011364, 1.07921364011364, 1.07921364011364, 1.07921364011364, 
        1.07921364011364, 1.07921364011364, 2.8566720117982, 2.8566720117982, 
        2.8566720117982, 2.8566720117982, 2.8566720117982, 2.8566720117982, 
        2.8566720117982, 2.8566720117982, 2.8566720117982, 2.8566720117982, 
        2.09930904742747, 2.09930904742747, 2.09930904742747, 2.09930904742747, 
        2.09930904742747, 2.09930904742747, 2.09930904742747, 2.09930904742747, 
        2.09930904742747, 2.09930904742747, 2.09930904742747, 1.43215872939721, 
        1.43215872939721, 1.43215872939721, 1.43215872939721, 1.43215872939721, 
        1.43215872939721, 1.43215872939721, 1.43215872939721, 1.43215872939721, 
        1.43215872939721, 1.43215872939721, 1.43215872939721, 2.21146503479172, 
        2.21146503479172, 2.21146503479172, 2.21146503479172, 2.21146503479172, 
        2.21146503479172, 2.21146503479172, 2.21146503479172, 2.21146503479172, 
        2.21146503479172, 2.21146503479172, 2.21146503479172, 2.21146503479172
        )), class = "data.frame", row.names = c(NA, -91L))

and I have created the heatmap of the correlations:

ggplot(data = melted_cormat, aes(Var2, Var1, fill = value)) 
  geom_tile(color = "white") 
  scale_fill_gradient2(low = "#2bc290", high = "#b6c1ff", mid = "#F9F7F5", 
                       midpoint = 0, limit = c(-1,1), space = "Lab", 
                       name="Magnitude of\nCorrelation")  
  theme_minimal()  
  theme(axis.text.x = element_text(angle = 45, vjust = 1, 
                                   size = 12, hjust = 1)) 
  coord_fixed()  xlab("")  ylab("")

But I would like to add a barplot to the plot in order to look like that:

Can I do that?

CodePudding user response：

This is possible (though not advisable since it makes for a messy and confusing plot). The secret is to make the x axis numeric, but give it the factor levels of Var2 as labels. Then plot vif as a bar plot and use a secondary axis to label it.

Start by explicitly converting Var2 to a factor:

melted_cormat$Var2 <- factor(melted_cormat$Var2, 
                             levels = c(paste0('X', 0:8), 'maxd', 'lag', 
                                        'tas', 'mean'))

And the plotting code is like this:

ggplot(data = melted_cormat, aes(as.numeric(Var2), Var1, fill = value))  
  geom_tile(color = "white")  
  geom_bar(stat = 'summary', fun = mean,
           aes(y = Var1, x = vif * 3), fill ='gold', position = 'identity',
           width = 0.5, color = 'orange', alpha = 0.5)  
  scale_fill_gradient2(low = "#2bc290", high = "#b6c1ff", mid = "#F9F7F5", 
                       midpoint = 0, limit = c(-1,1), space = "Lab", 
                       name="Magnitude of\nCorrelation")  
  scale_x_continuous(breaks = seq_along(levels(melted_cormat$Var2)),
                     labels = levels(melted_cormat$Var2),
                     sec.axis = sec_axis(~.x/3, name = 'vif'))  
  theme_minimal()   
  theme(axis.text.x.bottom = element_text(angle = 45, vjust = 1, 
                                          size = 12, hjust = 1)) 
  coord_fixed()  
  labs(y = NULL, x = NULL)