Contour plots and image plotting

We will now discuss the features Matplotlib provides to create contour plots and display images.

Contour plots

Contour lines (also known as level lines or isolines) for a function of two variables are curves where the function has constant values. Mathematically speaking, it's a graph image that shows:

f(x, y) = L

with L constant. Contour lines often have specific names beginning with iso- (from Greek, meaning equal) according to the nature of the variables being mapped.

There are a lot of applications of contour lines in several fields such as meteorology (for temperature, pressure, rain precipitation, wind speed), geography, oceanography, cartography (elevation and depth), magnetism, engineering, social sciences, and so on.

The absolutely most common examples of contour lines are those seen in weather forecasts, where lines of isobars (where the atmospheric pressure is constant) are drawn over the terrain maps. In particular, those are contour maps because...