SURVEYING

Surveying

it is the art of measuring horizontal and vertical distance between objects, of measuring angles between lines, of determining the direction of lines, and of establishing points by predetermines angular and linear measurements.

plane surveying and geodetic surveying

what are the types of surveying

plane surveying

the type of surveying in which the mean surface of the earth is considered as a plane, or in which its spheroidal shape is neglected. Great for mapping small areas

Geodetic surveying

the type of surveying which takes into account the true shape of the earth. Surveys employing the principles of geodesy are of high precision and generally extended over large areas

mining surveying

made to control, locate and map underground and surface works related to mining operationsc

construction survey

made to lay out, locate and monitor public and private engineering works

route survey

refers to those control, topographic, and construction surveys necessary for the location and construction of highways, railroads, canals, transmission lines, and pipelines

photogrammetric survey

made to utilize the principles of aerial photogrammetry, in which measurements made on photographs are used to determine the positions of photographed objects

astronomical survey

generally, it involves imaging or “mapping” of regions of the sky using telescopes

\
Ct = aL (T-T0)

what is the formula for temperature correction

coefficient of linear (or thermal) expansion

What is the “a” in temperature correction

Cp = (P-P0) L / aE

what is the formula for pull correction

Cross-sectional area of tape

what is the “a” in pull correction?

Elastic modulus of the steel

what is the “E” in pull correction

Cs = w^2 L^3 / 24 P^2

Formula for sag correction

weight of tape

what is the “w” in sag correction?

distance between supports

What is “L” in sag correction?

errors

the uncertainty of every measurement by any measuring instrument

systematic error

is an effect that changes all measurements by the same amount or by the same percentage. it is the cummulative error cause by different circumstances

instrumental error, imperfection in experimental technique, personal errors

what are the classification of systematic error

random/accidental error

errors which occur irregularly and hence are random with respect to sign and size

instrumental error

these errors arise due to imperfect design or calibration of the measuring instrument

imperfection in experimental technique

errors that will systematical affect the data and will occur due to the incorrect procedure

personal errors

such errors arise due to an individual’s bias, lack of proper setting of the apparatus or individual’s carelessness in taking observation without observing proper precautions

instrumental, personal, natural

what are the sources of error

instrumental

errors are caused by the instrument itself because of its imperfections and not calibrated well enough

personal

errors that are due to the poor judgement of the observer and other factors influencing human errors

natural

errors that are caused by natural phenomenon

compass surveying

is a branch of surveying in which the location of objects is located using angles and lines

traversing

it is the process used in compass surveying where different points in a plot are connected by using series of straight lines

true north

is the direction towards the fixed point we call the north pole

magnetic north

a point that continually shifts location based on the activity of earth’s magnetic fields

declination

the angle that the compass needle at a particular place and time makes with the true north

bearing

is an angle less than 90 degrees within a quadrant defined by the cardinal directions

azimuth

is an angle between o degree and 360 degree measured clockwise from north or south