A histogram shows the statistical frequency of data distribution within a dataset. In the case of remote sensing, the dataset is an image. The data distribution is the frequency of pixels in the range of 0 to 255, which is the range of 8-byte numbers that are used to store image information on computers.
In an RGB image, color is represented as a 3-digit tuple with (0,0,0, 0, 0) being black and (255,255,255) being white. We can graph the histogram of an image with the frequency of each value along the y-axis and the range of 256 possible pixel values along the x-axis.
Remember in Chapter 1, Learning about Geospatial Analysis with Python, in the Creating the simplest possible Python GIS section, when we used the Turtle ...
