Agriculture: Agricultural Systems Technology, Part 8
Question 1: Explain differential leveling in surveying.
Answer 1: Differential leveling is the determination of the relative elevations of at least two distinct points. These elevations may refer to mean sea level or a local marker. Relative elevations can be used in activities like constructing a drainage system, in which the slope direction must go the right way for there to be a proper flow. The reference point in differential leveling is the height of instrument (HI). For instance, when a telescope is used, the line of sight will be found at the elevation equal to the scope. Differential leveling may require the instrument to be set in a number of different places; this depends on factors such as the vertical and horizontal distances between points. Absolute elevation is not crucial in differential leveling.
There are lots of good resources about Agriculture that you can find available.
Question 2: Describe profile leveling in surveying.
Answer 2: Profile leveling is a form of differential leveling in which a series of points at measured intervals are placed along a line. An example of its use would be in building a road or ditch. In profile leveling, the elevations are calculated in the same manner as in differential leveling. Profile elevations are determined from ground readings. Cross sections are used in profile leveling. These are short profiles that are made perpendicular to the center line of what is being surveyed. These measurements are taken at regular intervals or when sudden changes occur in the centerline profile. Cross sections must extend a sufficient distance so that each side of the centerline provides a view of the terrain surrounding the area.
Question 3: Discuss the maintenance and care of surveying equipment.
Answer 3: Accurate surveying requires good, well-maintained equipment. Surveying equipment, such as transits or levels, is placed in carrying cases to limit jostling. The instruments should be stored inside the cases when they are not being used. It is important to keep the equipment clean and dry. This is especially true for the optical portions of the equipment. Remove mud and dirt from equipment such as tripods and level rods. This will help prevent rust. Equipment should be lubricated when recommended. Visual inspections of the equipment should also be performed. This includes checking for cracks or damage to receivers and cabling in global positioning satellite systems. Other specific maintenance includes checking level bubbles to ensure they are in adjustment.
Previous: Agriculture: Agricultural Systems Technology, Part 7 - Next: Agriculture: Animal Science, Part 1
|
