Plumb Line and Horizontal Reference Diagram - Engineering & Surveying Principle #215201 (License: Personal Use)

This schematic depicts a plumb line-a weighted string suspended from point Q-that hangs vertically under gravity, intersecting a horizontal reference line EF at point P. The diagram labels key components including the vertical line (QP), horizontal line (EF), and the plumb bob (P), illustrating fundamental principles of alignment in civil engineering and land surveying. Notation (b) suggests it is part of a series of instructional figures.

Used in educational resources, engineering textbooks, or surveying guides to explain vertical referencing, instrument calibration, or setup of leveling equipment; matches user intent seeking foundational geometric or measurement concepts.