CA PLS Exam Preparation

Comprehensive preparation for the California Professional Land Surveyor (PLS) exam. Based on the January 2025 Test Plan with 6 modules and 57 topics. Content adapted from CalTrans LS/LSIT Video Exam Preparation Course materials.

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Lesson 7

Control Networks

Control Networks

Overview

Control networks provide the framework for surveying projects, establishing consistent horizontal and vertical reference. Understanding network design, adjustment, and connection to geodetic control is essential.

Learning Objectives

  • Design effective control networks
  • Connect to geodetic control systems
  • Perform network adjustments
  • Evaluate network accuracy

Key Concepts

Network Design Principles

Effective control networks feature:

  • Adequate geometry for strength
  • Redundant observations for checking
  • Appropriate monument stability
  • Connections to existing control
  • Coverage of project area

Geodetic Control Connections

Connecting to national framework:

  • NGS control monuments
  • CORS and RTN networks
  • OPUS processing
  • Published coordinates and metadata
  • Datum and epoch considerations

Horizontal Control

Horizontal network considerations:

  • GPS/GNSS observations
  • Total station traverses
  • Triangulation/trilateration
  • Combined networks
  • Positional accuracy assessment

Vertical Control

Vertical network considerations:

  • Differential leveling connections
  • Published benchmarks
  • Orthometric vs. ellipsoid heights
  • Geoid models
  • Accuracy standards

Network Adjustment

Methods for combining observations:

  • Least squares adjustment
  • Error distribution
  • Residual analysis
  • Quality indicators
  • Constrained vs. minimally constrained

Key Terms

  • CORS: Continuously Operating Reference Station
  • OPUS: Online Positioning User Service
  • Network Accuracy: Uncertainty relative to datum

Practice Questions

  1. What factors should be considered in designing a control network?
  2. How are GPS observations connected to the National Spatial Reference System?

Based on CalTrans LS/LSIT Video Exam Preparation Course materials.