Which of the following is NOT included in the variables of symbolization?

Orientation is not typically considered one of the fundamental variables of symbolization in cartography. The primary variables of symbolization are value (which often refers to the color hue or intensity used to represent data), pattern (such as the arrangement of symbols), and size (which can indicate the magnitude or importance of a feature).

In the context of cartography, value helps to convey differences in data effectively through color gradients. Patterns provide visual differentiation and can indicate specific data types or categories. Size plays a crucial role by reflecting quantitative data through variations in symbol dimensions, allowing for immediate visual interpretation of the data's significance.

Orientation, while it may affect how symbols are perceived or interpreted, is not a foundational element that directly involves the representation of the quantity or quality of data in the same way that value, pattern, and size do.