What is the primary purpose of minor lights in navigation?

The primary purpose of minor lights in navigation is to serve as navigational aids within harbors and channels. These lights help to guide vessels safely through confined waters, where navigation can be more challenging due to traffic, shallow areas, and potential hazards. Minor lights typically provide essential guidance for mariners, indicating specific navigational routes and obstructions, thus enhancing maritime safety.

In contrast, the other options focus on different aspects of navigation. While some lights do indicate the presence of buoys, this is not the primary function of minor lights. Minor lights do not measure water depth, as that is typically accomplished through depth sounders or surveys. Additionally, the broadcasting of weather information is not a role assigned to minor lights, which are specifically designed to aid vessel navigation rather than to provide meteorological data.