Theory of Errors & Plane Table Surveying
Theory of Errors, Occurrence of Error- Imperfection in Instruments, Environmental Condition, Human Limitations & Carelessness, Type of Error– Gross Errors or Mistakes, Systematic or Cumulative Errors, Accidental or Random errors, Important Terminology- Precision, Accuracy, True Value, True Error, Most Probable Value (M.P.V), Principle of Least Square, Residual Error. Law’s of Weights, Probable Error– Probable Error in Single Measurements, Probable Error in Mean (MPV), Probable Error of Single Measurement of Weight, Error In Computed Result.
Plane Table Surveying, Accessories Used in Plane Table Surveying- Plane Table Board, Alidade (for orientation), Tripod (for stand), Level Tube/ Spirit Level (for leveling), Compass (for orientation), Plumbing Fork (for centering), Procedure, Setting up the Plane Table- Centering, Levelling, Orientation: Orientation with a Trough Compass, Orientation by Back-Sighting, Resection. Method Of Plane Table Survey– Radiation Method, Traversing Method, Intersection Method, Resection Method- Compass Method of Resection, Back Ray Method of Resection, Two Point Problem of Resection, Three Point Problem of Resection.
Topics
A theodolite is an important instrument used for measuring horizontal and vertical angles in surveying. The system of surveying in which the angles (both horizontal & vertical) are measured with the help of a theodolite, is called Theodolite surveying.
In compass surveying each control point is established with the help of linear and angular measurements and this process is termed as traversing. Traverse, Meridian, Bearing are discussed in detailed.