Center for Operational Oceanographic Products and Services staff member conducts tide station levelling in support of the US Army Corp of Engineers in Richmond, Maine. Levelling or leveling (; ) is a branch of, the object of which is to. Find the elevation of a given point with respect to the given or assumed. Establish a point at a given elevation with respect to the given or assumed.
Levelling is the measurement of using an optical levelling instrument and a or rod having a numbered scale. Common levelling instruments include the, the, the digital level, and the. Further information: Older instruments The wye level is the oldest and bulkiest of the older style optical instruments. A low-powered telescope is placed in a pair of clamp mounts, and the instrument then leveled using a, which is mounted parallel to the main telescope. The was developed by English civil engineer, while surveying the route of a proposed railway line from London to Dover. More compact and hence both more robust and easier to transport, it is commonly believed that dumpy levelling is less accurate than other types of levelling, but such is not the case. Dumpy levelling requires shorter and therefore more numerous sights, but this fault is compensated by the practice of making foresights and backsights equal.
Precise level designs were often used for large leveling projects where utmost accuracy was required. They differ from other levels in having a very precise spirit level tube and a micrometer adjustment to raise or lower the line of sight so that the crosshair can be made to coincide with a line on the rod scale and no interpolation is required. Automatic level. This article contains. The purpose of Wikipedia is to present facts, not to train. Please help either by rewriting the how-to content or by it to,.
(May 2015) Automatic levels make use of a compensator that ensures that the line of sight remains horizontal once the operator has roughly leveled the instrument (to within maybe 0.05 degree). The surveyor sets the instrument up quickly and doesn't have to relevel it carefully each time he sights on a rod on another point.
It also reduces the effect of minor settling of the tripod to the actual amount of motion instead of leveraging the tilt over the sight distance. Three level screws are used to level the instrument. Gun sight. Circular level (pond bubble). Levelling Screw.
Base Plate. Objective Lens. Focusing Knob. Horizontal fine motion screw. Horizontal circle window. Horizontal circle setting ring. Reticle adjusting screw cover.
Eyepiece Setting up an automatic level Set up the tripod at just above chest height. Make sure it is stable, and mount the level on the top.
Adjust the leveling screws until the pond bubble is centralised. As long as the pond bubble is central, the automatic compensators are able to finely level the instrument. To ensure this is the case, whilst looking through the scope, gently tap the level. The view will waver for a few moments before steadying.
Surveying Software Programs
If this does not happen, the instrument is not level enough for the compensators to cope, and needs adjustment. Sighting Sight towards the staff using the gun sight. Look through the eyepiece and focus the reticle by gradually turning the reticle focusing ring anti-clockwise. Turn the focusing knob to focus on the staff. Turn the fine motion screw to centre the staff in the field of view. Turn the focusing knob to eliminate parallax between the staff and reticle. The Reading the staff The staff starts at zero, on the ground.
Every 10 cm is a number, showing ( in meters to one decimal) the height of the bottom of what appears to be a stylised E (even numbers) or 3 (odd numbers), 5 cm high. The stems of the E or 3 and the gaps between them are each 10mm high. These 10mm increments continue up to the next 10 cm mark. To read the staff, take the number shown below the reticle. Count the number of whole 10mm increments between the whole number and the reticle. Then estimate the number of mm between the last whole 10mm block and the centre of the reticle.
The person holding the staff should endeavour to hold it as straight as possible. The leveller can easily see if it is tilted to the left or right, and should correct the staff-holder. However, it cannot easily be seen that the staff is tilted towards or away from the leveller.
In order to combat this possible source of error, the staff should be slowly rocked towards and away from the leveller. When viewing the staff, the reading will thus vary between a high and low point. The correct reading is the lowest value. Freddy krueger supreme edition glove.
Digital levels electronically read a bar-coded scale on the staff. These instruments usually include data recording capability. The automation removes the requirement for the operator to read a scale and write down the value, and so reduces blunders.
It may also compute and apply refraction and curvature corrections. Laser level.
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Main article: Laser levels project a beam which is visible and/or detectable by a sensor on the leveling rod. This style is widely used in construction work but not for more precise control work. An advantage is that one person can perform the levelling independently, whereas other types require one person at the instrument and one holding the rod. The sensor can be mounted on earth-moving machinery to allow automated grading. See also. References Wikimedia Commons has media related to.
. Overview of Surveying Technology (3 credits): This course introduces the student to the various methods and applications of land surveying in the real estate, construction and land development industries.
Students will also be introduced to the various technologies employed by professional land surveyors in accomplishing their work, including differential leveling, electronic distance measurement (EDM), electronic data collection, computer-aided design (CAD), the global positioning system (GPS) and geographical and land information systems (GIS/LIS). Prerequisite: ENGL1050 English Composition. Surveying Management I (4 credits): This course introduces the student to the fundamental theories and techniques for horizontal and vertical measurements with theodolites, automatic levels and steel tapes. Labs include projects in linear measurements, leveling, traversing and stadia surveys. Prerequisite: MATH1065 College Math C. Legal Aspects of Land Surveying I (3 credits): This course includes an introduction to the realm of real estate law that is essential to the practice of land surveying and the basics of land surveying research.
Real estate law and conveyancing terminology, evidence gathering and research theory will be taught. Key principles of boundary law will be explored such as the relative weight of evidence, sequential and simultaneous conveyances, easements and rights of way, and the public land survey system.
Prerequisite: ENGL1050 English Composition and SURV1200 Surveying Measurement I. Surveying Measurement II (4 credits): This course includes traverse calculation, error analysis, applications of coordinate geometry, horizontal and vertical curve calculations, introduction to geodetic survey principles, basic map projection calculations and the introduction to, and use of, data collection equipment and software. Labs include layout of horizontal and vertical curves, field techniques for boundary layout, data collection and site detail mapping.
Book Leveling Program
The final project in this course will involve the detailed surveying and mapping of a section of the campus suitable for use in engineering design, construction or conveyance. Prerequisite: SURV1200 Surveying Measurement I. Massachusetts Regulations Affecting the Surveying Profession (3 credits): This course involves the study of those regulations directly affecting the practice of land surveying in the Commonwealth of Massachusetts such as the Registration Law (MGL Chap. 81D-81T), the regulations of the Board of Registration of Professional Engineers and of Land Surveyors (250 CMR), the Subdivision Control Law (MGL Chap. 41), the Zoning Act (MGL Chap 40A) and the Massachusetts Land Court Manual of Instructions. Students will be introduced to other bodies of regulations often encountered in the practice of land surveying such as municipal subdivision regulations, the Wetlands Protection Act, and the Massachusetts Environmental Policy Act (MEPA). Prerequisite: ENGL1050 English Composition.
Legal Aspects of Land Surveying II (3 credits): Building on the principles taught in Legal Aspects of Land Surveying I, special boundary topics such as water boundaries, unwritten transfers and writing legal descriptions will be covered, along with the roles of statute and case law in the boundary decision process. Students will complete a final project that will involve the application of legal principles to an actual surveying problem, requiring them to make boundary decisions involving conflicting evidence. Prerequisite: SURV1500 Legal Aspects of Land Surveying I and SURV2200 Surveying Measurement II.