Distance Between Two
    Points
 Classes of Level
 Precision of Levelling
 Two Peg Test
 Field Procedures
 Procedural Rules
 Reduction Methods
 Adjustment of Misclosure

Procedural Rules

1. Always commence and finish a level run on a Benchmark (B.M. or T.B.M.). The Benchmark at the start may be different than that at the finish.

2. The length of foresight and backsight should be as equal as is practical.

3. The length of the lines of sight should be kept less than 100m and more conventionally 50m.

4. Staff readings of less than 0.5m should be avoided to prevent errors due to atmospheric refraction.

5. Change points should be located on suitable ground, for example the top of a pointed rock, or a nail placed in a footpath or road.