Which of the following is NOT one of the four principles of viewshed protection?

Viewshed protection involves strategies designed to preserve the visual integrity of landscapes by managing how development impacts scenic views. The principles of viewshed protection typically consist of methods that help evaluate, manage, and safeguard these visual resources effectively.

Accurate visual inventory and assessment is critical as it involves identifying and documenting the significant visual features of an area, providing a foundation for understanding how views can be affected by potential development. Enforcement mechanisms are equally essential, as they establish guidelines and regulations that govern development to prevent negative visual impacts. Furthermore, public opinion surveys for scenic quality engage the community, ensuring that the values and preferences of local residents regarding scenic views are considered in decision-making processes.

However, community income analysis does not directly relate to viewshed protection. While it might be beneficial to understand the socioeconomic context of an area when planning for development, it does not form a principle of viewshed protection itself, as it focuses more on financial aspects rather than the management of visual resources. Thus, this option is not aligned with the core principles essential for protecting viewshed integrity.