This is a permanent reference mark or point established for use by Land Surveyor’s in measuring differences in elevation. It is identification symbols on stone, metal, or other durable matter permanently fixed in the ground and from which differences of elevations are measured as in tidal observations or topographical surveys (datum). A benchmark is the standard or base from which specific estimates are made. It is a surveyor fixed point of reference for use in leveling the reduced level of the point in relation to some datum being known.
Definitions of benchmark on the Web:
- a Land Surveyor’s mark on a permanent object of predetermined position and elevation used as a reference point – cogsci.princeton.edu/cgi-bin/webwn
- A measurement or standard that serves as a point of reference by which process performance is measured – ch.doe.gov/programs/iap/glossary.html
