Fore Sight
Summary
Fore Sight - In levelling, a fore sight is taken immediately before the optical level is moved to a new location.
Technical Information
After all grid points within range of the optical level have been measured, it is necessary to move the optical level to a new location.
There is a chance that, in its new location, the optical level will be higher or lower than it was in its old location.
Therefore, it is necessary to:
- Take a measurement (fore sight) from a point before the optical level is moved.
- Take a measurement (back sight) from the same point once the optical level is set up in its new position.
- Calculate the difference in elevation between the old and new location of the optical level.
Related Definitions
Reference Grid , Intermediate Sight , Back Sight , Optical Level , DatumResources
California Department for Transportation: Surveys Manual; Chapter 8Please share this definition:
