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Types of Surveys & Applicability

Archaeological Survey : used to accurately assess the relationship of archaeological sites in a landscape or to accurately record finds on an archaeological site.

As-Built Survey : a survey conducted several times during a construction project to verify , for local & state boards that work authorized was completed to specifications set on plot plan or site plan.

Bathymetric Survey : a survey carried out to map the seabed profile.

Boundary Survey: the actual physical extent of property ownership, typically witnessed by monuments or markers are measured & a map or plot is drawn.

Construction Surveying: the process of establishing & marking the position & detailed layout of new structures for subsequent construction.

Deformation Survey: a survey to determine if a structure or object is changing shape or moving.

Engineering Surveys: those surveys associated with engineering design often requiring geodetic computations beyond normal civil engineering practise.

Hydrographic Surveys: a survey conducted with the purpose of mapping the coastline & seabed for navigation, engineering or resource management purpose.

SURVEYING

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Surveying is the technique & science of accurately determing the terrestrial or three dimensional space position of points & the distances & angles between them.

These points are usually, but not exclusively, associated with positions on the surface of the earth, & are often used to establish land maps & boundaries for ownership or governmental purpose.In order to accomplish their objectives surveyors use elements of geometry, engineering, trignometry, mathematics, physics & law

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The Science of Surveyors
Surveyors & engineers understand the importance of geographic data.Surveyors use precise instruments, procedures & computations to accurately locate & define geographic features while conducting field surveys that range from cadastral to engineering construction layout. Engineers design & build structures & infrastructures on geography measured by surveyors.

How essential it is?
Surveying has been an essential element with development of the human environment since the beginning of recorded history(5000 years ago) & it is a requirement in the planning & execution of nearly every form of construction. it is most familiar modern uses are in the fields of transport , building and construction, communication , mapping & the definition of legal boundaries for land ownership.

From History..........
Surveying techniques have existed throughout much of recorded history.In ancient Egypt , when the Nile river overflowed its banks & washedout farms boundaries, were re-established through the application of simple geometry.The nearly perfect squareness & north-south orientation of the Great Pyramid of Giza, built 2700 BC affairms the Egyptians command of Surveying.
Historically angles & distances were measured using a variety of means , such as chains with links of a known length , for instance a Gunter's chain or measuring tapes made of steel or invar.In order to measure horizontal distances , these chains or tapes would be pulled taut according to temperature , to reduce sagging & slack. Additionaly attempts to hold the measyring instrument level would be made. In instances of measuring up a slope , the surveyor might have to "break"( break chain) the measurement- that is, raise the rare part of the tape, plumb from where the last measurement ended.

Technology ..............

As late as the 1990's the basic tools used in planar surveying were a tape measure for determining shorter distances, a level for determining heights or elevations & a theodolite set on a tripoid to measure angles (horizontal & vertical) combined with triangulation. Starting from a benchmark, a position with known location & elevation, the distances & angles to a known the point are measured. A more modern instrument is a total station , which is a theodolite with an Electronic Distance Measurement device (EDM) & can also be used for leveling when set to the horizontal plane. Since their introduction total stations have made technological shift from being optical-mechanical devices to being fully electronic with an onboard computer & software.