Differential-leveling data include the names of the rodmen is recorded on DA Form or any other single-sheet recording form authorized by the party chief Figure The portable base plate is made of cast iron with a machined-steel point to place the rod on. The bench marks should not include objects subject to tampering or removal.
The exact location of the bench mark should be carefully selected, then sketched and recorded in notes, a field book or a data collector.
The observer performs the observations, is responsible for the care and condition of the instrument and accessories, ensures that the maximum sight distance is not exceeded when moving the level from the last foresight level rod to the next instrument setup, inspects the level tripod to ensure that all parts are secure and adjusted properly, deliberately places the level to provide a stable platform, carefully levels the instrument and reads the appropriate data, and never leaves the geodetic level unattended.
Perform a C-check at about the same time each day. The Level The compensator type, automatic engineer level is made by various manufacturers, and is a precision, self-leveling instrument, equipped with a built-in compensator that automatically maintains a horizontal line of sight and has a telescope with approximately power magnification.
If the top interval is LARGER than the bottom, ADD Differential leveling correction factor to the recorded center-wire reading to obtain the mean center-wire value to four decimal places.
References in periodicals archive? Consideration should be given to construction activities such as utility re-location proposed within the ROW. The compensator is sensitive to shock and must be kept nearly upright at all times.
The marlinspike is a stainless-steel pin that is driven into soft surfaces at an angle and a depth sufficient to support the level rod.
Turning points should be marked when used so as to insure that the rod is in the exact same place when the backsight and foresight are taken. Cleaning and adjustment or repair should be done as needed.
Balance shot distances — The rodman and instrument man must work as a team to balance the backsight and foresight distances.
Electronic digital levels use a barcode marked rod. Chapter 5 Differential leveling Both profile and differential leveling use backsights, foresights, benchmarks, and turning points.
Operate and adjust the motions. The difference in height and distance is then determined. They are solid, well protected points that can be relied upon to remain undisturbed and unchanged.
The numerical value obtained during the C-check gives the correction to the observed DE because of the inequality of sight distances for a single setup or the inequality of the accumulated sight distance for a section of differential leveling. If not, have the instrument serviced.
Leveling rods are manufactured of metal, wood, or fiberglass. When the bubble is centered, the compensator takes over and maintains a horizontal line of sight. Leveling should be avoided during hot temperatures. In surveying, the referenced datum is typically the MSL.
Some of the basic components for leveling are a level, a tripod, rods, and accessories.
Points with a small, sharply defined top are preferred to large flat surfaces. General data collected for a DTM, topographic mapping, cross sections, or other purpose. Leapfrog the rods forward.
A thorough knowledge of leveling principles and proper application of methods and equipment will prevent costly delays and generate the needed results and accuracy. The duties of each member are identified as follows: The marked rod is observed and the readings are recorded first for each setup.
Differential Leveling - control bench marks, cross-sections, point elevations Trigonometric Leveling - for Digital Terrain Model DTM3D Model Indirect leveling and location by measuring horizontal distances and vertical angles Three-dimensional coordinates - both horizontal position and elevation are computed by processing the measurements GPS survey - given the appropriate equipment, procedure and data collection.
They are graduated in feet or meters and can be read directly to the nearest tenth of a foot or centimeter Figure Equipment The Rod Rods are, in essence, a tape supported vertically, and used to measure the vertical distance difference of elevation between a horizontal line of sight and a required point above or below it.Differential leveling requires the use of a surveyor's level together with graduated measuring rods.
An elevation is a vertical distance above or below a referenced datum. Section 2: Differential Leveling Anchor: #i Overview. Differential leveling is the process of measuring vertical distances from a known elevation point to determine elevations of unknown points.
Differential Leveling Overview Differential leveling is the process of measuring vertical distances from a known elevation point to determine elevations. Differential Leveling Importance of Vertical Positions A vertical positionis the height of a point relative to some reference surface, such as mean sea level, a geoid, or an ellipsoid.
The roughlyvertical control points in the U.S. Differential Leveling Survey Specifications When multiple leveling survey loops interconnect to form a network, such as in corridor or project control, points common to two or more loops will be adjusted by application.
For differential leveling, the only critical feature of station identification is that an organized method be used so that the system is clear to the user of the notes. In differential leveling, each station is used as a backsight and a foresight.Download