What is the primary output of conducting plane surveying?

The primary output of conducting plane surveying involves the establishment of precise horizontal control points. In plane surveying, the focus is on measuring horizontal distances and angles to determine the position of points on the Earth's surface. This is crucial for a variety of applications, including mapping, land use planning, and construction.

The creation of horizontal control points is essential because these points serve as reference markers that can be used in future surveys and engineering projects. They ensure that all measurements are aligned and consistent with a known coordinate system, which is vital for accuracy and reliability in any subsequent work conducted in the surveyed area.

While the other options, such as a topographic map, construction plans, or legal descriptions, are important aspects of surveying, they build upon the foundational data provided by horizontal control points established during plane surveying. Thus, the precise coordinates obtained through plane surveying are fundamental in supporting a wide range of engineering and mapping tasks.