Direct Reading Optical Rods
Direct Reading Grade Rods, or True Elevation Grade Rods (also known as Lenker Rod style) is a Grade Rod with a face that allows the user to set the actual benchmark elevation, or any elevation, above or below the benchmark into the rod. The actual true elevation above sea level is read on these rods, thus eliminating errors caused by adding or subtracting. Since no math is involved, grade shots are much faster than conventional style rods. On most job sites, the bench elevation is typically established by survey, and all elevations on that project are above or below that primary bench elevation.
Benchmark - Elevation 2352.50 - Read On Rod As 2.50
Bldg. A Footing - Elevation 2351.50 - Read On Rod As 1.50
Bldg. B Finish Floor - Elevation 2353.85 - Read On Rod As 3.85
Catch Basin #12 - Elevation 2349.28 - Read On Rod As 9.28
In the USA, these elevations are typically represented in feet, tenths, and hundredths of a foot as per the example above.
The LaserLine Optical Version Direct Reading/True Elevation Rod is used with optical instruments and have no special rail for the laser detector like a Laser Version Direct Reading Grade Rod. All tape faces on the Optical Version Direct Reading Grade Rods have large scales so are easy to read at distance when using an optical instrument.