Skip to contents

Visualize Thermal Matrix as 2D Heatmap

Source: R/visualization.r
plot_thermal_heatmap.Rd

Generates a high-quality raster plot of the thermal data using the 'ggplot2' framework. This function allows for quick visualization of raw or processed matrices with customizable perceptually uniform color scales (viridis).

Usage

plot_thermal_heatmap(img_obj, use_processed = TRUE, palette = "inferno")

Arguments

img_obj

A 'BioThermR' object.

use_processed

Logical. If TRUE (default), plots the 'processed' matrix (showing masking effects). If FALSE, plots the original 'raw' data.

palette

String. The color map option from the 'viridis' package. Options include: "magma", "inferno", "plasma", "viridis", "cividis". Default is "inferno".

Value

A ggplot object.

Details

The function performs the following steps:

  • Converts the thermal matrix into a long-format data frame suitable for ggplot.

  • Renders the image using geom_raster.

  • Maps temperature to color using the specified 'viridis' palette.

  • Ensures the aspect ratio is preserved (coord_fixed) so the image does not appear distorted.

  • Sets NA values (masked background) to transparent.

Since the output is a standard ggplot object, layers can be added subsequently (e.g., new titles or annotations).

Examples

if (FALSE) { # \dontrun{
# Standard plot
p <- plot_thermal_heatmap(my_obj)
print(p)

# Customize plot (e.g., change title)
p + ggplot2::ggtitle("Subject A - Cold Exposure")
} # }