Projection operations are mathematical techniques used to transform data or points in a higher-dimensional space into a lower-dimensional space. This is often done to simplify complex data while retaining essential features. For example, in computer graphics, projection operations help render 3D objects onto a 2D screen, making it easier for users to visualize scenes. In the context of linear algebra, projection operations can be used to find the closest point on a subspace to a given point. This is useful in various applications, such as data analysis and machine learning, where reducing dimensions can enhance performance and interpretability.