What does the term "WELS" refer to?

The term "WELS" refers to the "Western Line of Eastern States," which is a designation that helps define a specific geographic boundary pertaining to regulations and management practices within Maine. This term is primarily used in the context of wildlife laws and various state regulations. Understanding geographical boundaries is essential in many environmental and regulatory contexts as they often delineate where certain rules apply, particularly concerning land use and wildlife management in a state like Maine.

The other options, while they may relate to various aspects of geography, land management, or navigation, do not accurately capture the specific meaning and application of "WELS." For instance, land elevation measurements and navigational boundaries serve different practical purposes and communicate entirely different types of information unrelated to the state's jurisdictional lines.