R/Heatmap.R

In Mendyvandervliet/HourlyPrecipExtr:

# Correlation heatmap with Pearson method, to visualize correlation matrix

#' Function to obtain correlation heatmap

#' @import ggplot2
#'
#' @export
heatmap <- function(data){
  cormat <- round(cor(data),3)
  cormat <- reorder_cormat(cormat)               # Reorder the correlation matrix
  upper_tri <- get_upper_tri(cormat)
  melted_cormat <- melt(upper_tri, na.rm = TRUE) # Melt the correlation matrix

  ggheatmap <- ggplot(melted_cormat, aes(Var2, Var1, fill = value))+
    geom_tile(color = "white")+
    scale_fill_gradient2(low = "blue", high = "red", mid = "white",
                         midpoint = 0, limit = c(-1,1), space = "Lab",
                         name="Pearson\nCorrelation") +
    theme_minimal()+ # minimal theme
    theme(axis.text.x = element_text(angle = 45, vjust = 1,
                                     size = 12, hjust = 1))+
    coord_fixed()
  ggheatmap +
    geom_text(aes(Var2, Var1, label = value), color = "black", size = 4) +
    theme(
      axis.title.x = element_blank(),
      axis.title.y = element_blank(),
      panel.grid.major = element_blank(),
      panel.border = element_blank(),
      panel.background = element_blank(),
      axis.ticks = element_blank(),
      legend.justification = c(1, 0),
      legend.position = c(0.6, 0.7),
      legend.direction = "horizontal")+
    guides(fill = guide_colorbar(barwidth = 7, barheight = 1,
                                 title.position = "top", title.hjust = 0.5))
}