Home Page

Celestial Navigation

Celestial Navigation - the book

Get a copy


Permanent Tables

Ephemeral Tables

Additions & Errata

About the Author




Precise Levelling

PL more pix

Gyrotheodolite Measurements

Gyro more pix

Purchase Order Form

In Performance

Mark Breach

Christine Breach

Mark Breach's CV

Astrogeodetic Levelling - PhD Thesis

Jaguar 27


Precise Levelling


 Videos - now also available as a DVD   


Part 1 Introduction
Why do we need Precise Levelling? Precision of modern instruments. What makes precise levelling precise? Precise equipment and precise procedures.

Part 2 Precise Levelling Equipment
Tilting and automatic precise levels. The micrometer. Invar staves with dual scales and supports. Change plates. Conventional and removable wall mounted bench marks. The precise levelling team.

Part 3 Procedures
2 peg test. Booking form - dual scales. Reconnaissance. Refraction. Care of the equipment. Wind. Stability. 21 rules of procedure for minimizing errors. How the rules are implemented. Checks upon observations and computations.

Part 4 Example procedure
2 bays of precise levelling between bench marks to show the practical application of the procedures described in Part 3.

Part 5 Exercise
An interactive exercise that uses 4 bays of precise levelling. Watch the video as the observer, and then complete the computations and checks. Can be used by lecturers as course work for assessment.

Part 6 Gap Crossing
How to use precise levelling equipment to transfer height across a river or other inaccessible gap that is wider than normal precise levelling will allow.

Total running time approx. 50 minutes

How to Get a copy      Precise Levelling More Pictures