Histograms are simple, yet it's important to get the right data into them. We will cover histograms in 2D for now.
Histograms are used to visualize estimations of distribution of data. Generally, we use a few terms when speaking of histograms. Vertical rectangles represent frequencies of data points within a particular interval, called a bin. Bins are created at fixed intervals so the total area of a histogram equals the number of data points.
Instead of using absolute values of data, histograms can display relative frequencies of data. When this is the case, the total area equals 1.
Histograms are often used in image manipulation software as a way to visualize image properties, such as distribution of light in a particular color channel. Further, these image histograms can be used in computer vision algorithms to detect peaks aiding in edge detections, image segmentation, and so on.
In Chapter 5, Making 3D Visualizations, we have recipes that deal with 3D histograms.
