Which command measure is used to control and coordinate military operations in land forces?

The command measure used to control and coordinate military operations among land forces is a Phase Line. Phase Lines are utilized to establish specific geographical points or markers on the battlefield. They help in synchronizing movements and operations by providing a clear reference for units to orient themselves with respect to each other and the overall operational plan.

By marking progress along these lines, commanders can assess their units' readiness and positioning, ensuring that all forces are operating cohesively towards the same objectives. Phase Lines also facilitate effective communication and the coordination of fire support, allowing for timely engagements and the adjustment of tactics as necessary.

In contrast, the other options represent different concepts. A Fire Support Area is designated for coordinating artillery and air support within a specific zone, focusing on fire assets rather than overall movement. Boundaries typically define the limits of command or operational areas between units, but do not serve the same purpose of coordination for progressing through an operation. A Fire Support Station refers specifically to points where fire support is delivered from, which again does not encompass the wider coordination aspect that Phase Lines provide.