ANGLE REDUCTION AND MERIDIAN CONVERGENCE

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ANGLE REDUCTION ANDMERIDIAN CONVERGENCE
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Learning Objectives

• After this lecture you will be able to
• Reduce measured angles for geodetic calculations
• Apply meridian convergence

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Lecture Outline

• SP1
• Reducing observed angles to spheroid
• Diagrams
• Meridian Convergence
• Geodetic Traverses
• Conclusion

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SP1 Requirements

• In Study Book

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Reduction of Measured Angles to the Spheroid

• Deflection of Verticals Correction
• Geoid and ellipsoid normals different
• Skew Normals Correction
• Normals at each end not parallel
• Correct to eliminate effect of two normal
  sections
• Laplace Correction
• Relationship between astronomical observed and
  geodetic azimuths
• Used to correct astronomical azimuths

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Sample Data

• We will cover these in next Prac/Tutorial
• Indicative order of magnitude
• Deflection correction 0.063
• Skew normal correction 0.003
• Laplace correction -60.72

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Diagrams
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Diagrams
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Meridian Convergence
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Geodetic Traverse - Several Diagrams
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Usual Diagram
Another way of depicting the same diagram is
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Geodetic Traverse - Single Diagram
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Meridian Convergence - (??)
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Meridian Convergence - (??)
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Meridian Convergence - (??)
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Summary

• We investigated
• SP1 requirements
• Corrections for
• Deflection of Verticals
• Skew Normals
• Laplace Corrections
• Meridian Convergence
• Geodetic diagrams

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Conclusion

• You can now
• Reduce measured angles to a form in which they
  can be used for geodetic calculations
• Calculate and apply meridian convergence

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Self Study

• Read relevant module in study materials

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Review Questions