Learning Geospatial Analysis with Python - Second Edition

Creating histograms

A histogram shows the statistical frequency of the data distribution in 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 used to store image information on computers. In an RGB image, color is represented as a three-digit tuple with (0,0,0, 0, 0) as black and (255,255,255) as 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.

In Creating the simplest possible Python GIS section of Chapter 1, Learning Geospatial Analysis with Python, we used the turtle graphics engine included with Python to create ...