R/plot_auxindex.R

In goodekat/ggResidpanel: Panels and Interactive Versions of Diagnostic Plots using 'ggplot2'

# Residual vs Index Plot.

# Creates a residual plot with the input residuals and predicted values
plot_auxindex <- function(resid, smoother, theme, axis.text.size, title.text.size, title.opt){

  ## Creation of Values to Plot -----------------------------------------------------

  # Create a data frame with the residuals
  model_values <- data.frame(Residual = resid)

  # Create a variable for observation number
  model_values$Observation <- 1:length(model_values$Residual)

  ## Creation of Plot ---------------------------------------------------------------

  # Create the residual plot
  plot <- ggplot(data = model_values, aes_string(x = "Observation", y = "Residual")) +
    geom_point() +
    geom_abline(slope = 0, intercept = 0, color = "blue") +
    labs(x = "Observation Number", y = "Residuals")

  # If smoother is set to true, add it to the plot
  if (smoother == TRUE){
    plot <- plot +
      geom_smooth(method = "loess", se = FALSE, color = "red", size = 0.5)
  }

  # Add theme to plot
  if (theme == "bw"){
    plot <- plot + theme_bw()
  } else if (theme == "classic"){
    plot <- plot + theme_classic()
  } else if (theme == "gray" | theme == "grey"){
    plot <- plot + theme_grey()
  }

  # Set text size of title and axis lables, determine whether to include a title,
  # and return plot
  if(title.opt == TRUE){
    plot +
      labs(title = "Index Plot") +
      theme(plot.title = element_text(size = title.text.size, face = "bold"),
            axis.title = element_text(size = axis.text.size))
  } else if (title.opt == FALSE){
    plot + theme(axis.title = element_text(size = axis.text.size))
  }

}