What do combined drawings in a plan and profile indicate?

Combined drawings in a plan and profile are essential in surveying and civil engineering as they provide a comprehensive view of a facility's geometry. When you see such drawings, they effectively illustrate both the horizontal layout (the plan view) and the vertical layout (the profile view) of the facility.

This means that option A is correct because it highlights that these drawings detail the elevation and horizontal location of structures within a specific area. The plan view shows where these structures will be located on the ground, while the profile view provides critical information about their elevation relative to a baseline, such as sea level or ground level. This information is vital for understanding the terrain, drainage, and other geometric relationships in the design and construction of infrastructure projects.

The other options address aspects that, while important in specific contexts, are not the primary purpose of combined drawings in plan and profile. Weight distribution and types of materials would be addressed in other documentation related to structural engineering rather than simply in combined drawings, and measurement errors pertain more to survey accuracy rather than the representation of the facility's geometry itself.