In Chapter 1, Visualization as a Tool to Understand Data, we introduced the concept of scalar field, which is just a mathematical term used to describe the position-based values of a scalar quantity. Let's recap the example given in Chapter 1, Visualization as a Tool to Understand Data. Pressure, temperature, potential, and other physical values are often associated with coordinates to quantify the spatial variation of the physical parameter. To measure the temperature of a big space, instead of taking a single reading at a certain position, it makes better sense to measure the temperature at different locations and present them in a sorted manner.

A discrete scalar field is a set of such coordinates—scalar tuples. In this section, we will demonstrate how to visualize contours from these datasets (and why they are useful). In an effort to maximize our exposure to scientific datasets, we will work with a protein molecule to build a molecular visualization...