leveling

chapter seven

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Digital Levels

Just as distance and angle measurement have gone electronic, electronics are now a part of the leveling process. Digital levels that read barcode rods are now a part of the everyday surveying equipment used on the construction jobsite. Digital levels are easy to operate and are quick and accurate in reading the rod. They are available in various sizes and shapes, but essentially do the same thing—read a rod electronically. In addition to being able to perform normal leveling operations of determining eleva-tions, many of these instruments also have data collection capability. This capability eliminates reading errors that occur when humans are involved in reading the rod and recording the data.

Although the exact operation of digital levels varies from manufacturer to manufacturer, digital levels are typically operated by sighting onto the barcode rod and simply pushing one button—the reading is taken within a few seconds. Readings can be displayed in either feet or meters. In addition to rod reading, the elevation at the rod can also be displayed, as well as the distance to the rod.

Digital levels can be effectively used anywhere on the jobsite for any type of leveling application. Examples include top of curb, grade beams, as-builts, benchmarks, and so forth. Digital levels are especially useful when running leveling loops to establish elevations on control points and temporary benchmarks.

It should be noted that many of the standard practices that apply to optical levels still apply to digital levels. There are still the possibilities of curvature and refraction errors, line of sight errors from unbalanced sights, errors by the rod not being plumb, and other common leveling errors. The user of a digital level should carefully read the owner’s manual and follow suggested procedures in addition to following standard leveling practices.

Level Rods

In addition to the leveling instrument, a level rod is required to be able to transfer elevations from one point to another. The level rod is nothing more than a graduated pole held vertically and read by the person at the instrument. The reading taken can be used to determine elevations.

Level rods are available in many sizes, shapes, and colors. They are made of wood, fiberglass, and metal, or a com-bination of these materials. There are one-piece rods, two-piece rods, three-piece rods, six-piece rods, etc. Some have a square cross-section and others are round or oval. Some are less than 10 feet long while others are up to 30 feet long. Practically whatever type of rod a field engineer needs is available. Level rods are named after