Surveying 1- PRELIM

Plane Surveying

the process of surveying by assuming that the earth is flat.

Geodetic Surveying

a process of surveying by considering the curvature or spherical shape of the earth.

City Survey

an extensive co-ordinated survey of the area within the limits of a municipally made for the purposes.

Forestry Survey

survey executed in connection with forest management and mensuration, and the production and conservation of forest land

Hydrographic Survey

They are of general importance in connection with navigation development of water supply and resources, flood control, irrigation and etc.

Topographic Survey

locates all surface features of a property, and depicts all natural and artificial features and elevations.

Route Survey

a data collection operation to gather information about the proposed route of a roadway, utility pipe, or railway.

Photogrammetric Survey

the branch of surveying in which maps are prepared from photo-graphs taken from ground or air stations.

Chains and tapes

measuring distances (horizontal)

Level

simple instrument designed to determine whether a surface is level or plumb (vertical)

Field notes

prepared to record all pertinent information, measurements, calculations, sketches, and observations made by the surveyor during the course of a survey

surveyor

professional person with the academic qualifications and technical expertise to conduct one, or more, of the following activities;

-to determine, measure and represent the land, three-dimensional objects,
point-fields, and trajectories;
-to assemble and interpret land and geographically related information;

Land Information Systems (LISs) and Geographic Information Systems (GISs)

areas of activity that have rapidly assumed positions of major prominence in surveying

Transits and Theodolites

These tools are used to measure both horizontal and vertical angles.

error

difference between a measured quantity and its true value, caused by imperfection in the measuring instrument, by the method of measurement, by natural factors such as temperature, or by random variations in human observation

Systematic Errors

repetitive errors that are caused by imperfections in the surveying equipment

Accidental Errors

difference between a true quantity and a measurement of that quantity that is free from blunders or systematic errors.

Mistakes

a significant mistake caused by human error

Mistakes

it is due to the inattention or carelessness of the it is due to the inattention or carelessness of the surveyor

discrepancy

difference between two observed values of the same quantity

Precision

the degree of refinement or consistency of a group of observations and is evaluated on the basis of discrepancy size

Accuracy

the absolute nearness of observed quantities to their true values

Most Probable Value

If two or more measurements of the same quantity are made, usually different values are obtained due to random errors

Error of Closure

difference between a measured quantity and its true, or actual, value

Relative Accuracy

For horizontal distances, the ratio of the error of closure to the actual distance

Weights are inversely proportional to the square of the corresponding probable errors.

W∝1/e^2

Weights are also proportional to the number of observations.

W∝ N

W∝1/D

Errors are directly proportional to the square roots of distances.