Surveying

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For other uses, see Surveyor (disambiguation).

Surveyor at work with a leveling instrument.

Table of Surveying, 1728 Cyclopaedia

Surveying is the technique and science of accurately determining the terrestrial or three-dimensional space position of points and the distances and angles between them. These points are usually, but not exclusively, associated with positions on the surface of the Earth, and are often used to establish land maps and boundaries for ownership or governmental purposes. In order to accomplish their objective, surveyors use elements of geometry (Greek: measuring the Earth), engineering, trigonometry, mathematics, physics, and law.

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

1 Method
2 Origins
3 Types of Surveys & Applicability
4 Surveying as a career
- 4.1 Building Surveying
- 4.2 Quantity Surveying
5 Land surveyor
6 See also
7 Famous surveyors
8 External links
9 Educational Institutions

[edit] Method

Historically, angles and distances were measured using a variety of means, such as chains with links of a known length, for instance a Gunter's Chain (see Edmund Gunter), 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 and slack. Additionally, attempts to hold the measuring 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 rear part of the tape upward, plumb from where the last measurement ended.

Historically, horizontal angles were measured using a compass, which would provide a magnetic bearing, from which deflections could be measured. This type of instrument was later improved upon, through more carefully scribed discs providing better angular resolution, as well as through mounting telescopes with reticles for more precise sighting atop the disc (see theodolite). Additionally, levels and calibrated circles allowing measurement of vertical angles were added, along with verniers for measurement down to a fraction of a degree- such as a turn-of-the-century Transit (surveying).

The simplest method for measuring height is with an altimeter — basically a barometer — using air pressure as an indication of height. But for surveying more precision is needed. Toward this end, a variety of means, such as precise levels, have been developed. Levels are calibrated to provide a precise plane from which differentials in height between the instrument and the point in question can be measured, typically through the use of a vertical measuring rod.

As late as the 1990's the basic tools used in planar surveying were a tape measure for determining shorter distances, a level for determine height or elevation differences, and a theodolite, set on a tripod, with which one can measure angles (horizontal and vertical), combined with triangulation. Starting from a benchmark, a position with known location and elevation, the distance and angles to the unknown point are measured. A more modern instrument is a total station, which is a theodolite with an electronic distance measurement device (EDM) and can also be used for leveling when set to the horizontal plane. Since their introduction, total stations have made the technological shift from being optical-mechanical devices to being fully electronic with an onboard computer and software. Modern top-of-the-line total stations no longer require a reflector or prism (used to return the ambient light used for distancing) to return distance measurements, are fully robotic, and can even e-mail point data to the office computer and connect to satellite positioning systems, such as a Global Positioning System (GPS). Though GPS systems have increased the speed of surveying, they are still only accurate to about 20 mm.^{[citation needed]} As well GPS systems do not work in areas with dense tree cover. It is because of this that total stations have not completely phased out earlier instruments. Robotics allows surveyors to gather precise measurements without extra workers to look through and turn the telescope or record data. A faster way to measure (no obstacles) is with a helicopter with laser echolocation, combined with GPS to determine the height of the helicopter. To increase precision, beacons are placed on the ground (about 20 km apart). This method reaches a precision of about 5 mm.

With the triangulation method, one first needs to know the horizontal distance to the object. If this is not known or cannot be measured directly, it is determined as explained in the triangulation article. Then the height of an object can be determined by measuring the angle between the horizontal plane and the line through that point at a known distance and the top of the object. In order to determine the height of a mountain, one should do this from sea level (the plane of reference), but here the distances can be too great and the mountain may not be visible. So it is done in steps, first determining the position of one point, then moving to that point and doing a relative measurement, and so on until the mountaintop is reached.

[edit] Origins

Surveying techniques have existed throughout much of recorded history. In ancient Egypt, when the Nile River overflowed its banks and washed out farm boundaries, boundaries were re-established through the application of simple geometry. The nearly perfect squareness and north-south orientation of the Great Pyramid of Giza, built c. 2700 BC, affirm the Egyptians' command of surveying.

The Egyptian land register (3000 BC).
Under the Romans, land surveyors were established as a profession, and they established the basic measurements under which the empire was divided, such as a tax register of conquered lands (300 AD).
In England, The Domesday Book by William the Conqueror (1086)
- covered all England
- contained names of the land owners, area, land quality, and specific information of the area's content and habitants.
- did not include maps showing exact locations
Continental Europe's Cadastre was created in 1808
- founded by Napoleon I (Bonaparte), "A good cadastre will be my greatest achievement in my civil law", Napoleon I
- contained numbers of the parcels of land (or just land), land usage, names etc., and value of the land
- 100 million parcels of land, triangle survey, measurable survey, map scale: 1:2500 and 1:1250
- spread fast around Europe, but faced problems especially in Mediterranean countries, Balkan, and Eastern Europe due to cadastre upkeep costs and troubles.

A cadastre loses its value if register and maps are not constantly updated.

Large-scale surveys are a necessary pre-requisite to map-making. In the late 1780s, a team from the Ordnance Survey of Great Britain, originally under General William Roy began the Principal Triangulation of Britain using the specially built Ramsden theodolite.

[edit] Types of Surveys & Applicability

An all-female surveying crew in Idaho in 1918.

ALTA/ACSM Survey: a surveying standard jointly proposed by the American Land Title Association and the American Congress on Surveying and Mapping that incorporates elements of the boundary survey, mortgage survey, and topographic survey. ALTA/ACSM surveys, frequently shortened to ALTA surveys, are often required for real estate transactions.
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 and state boards, that the work authorized was completed to the specifications set on the Plot Plan or Site Plan. This usually entails a complete survey of the site to confirm that the structures, utilities, and roadways proposed were built in the proper locations authorized in the Plot Plan or Site Plan. As-builts are usually done 2-3 times during the building of a house; once after the foundation has been poured; once after the walls are put up; and at the completion of construction.
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, such as (typically iron rods, pipes or concrete monuments in the ground, but also tacks or blazes in trees, piled stone corners or other types of monuments) are measured, and a map, or plat, is drawn from the data. NOTE: The willful destruction and or removal of above said monuments is illegal in the United States. These acts will always result in fining and rarely, but not never, in jailtime.
Construction surveying (otherwise "lay-out" or "setting-out"): the process of establishing and marking the position and detailed layout of new structures such as roads or buildings for subsequent construction. In this sense, surveying may be regarded as a sub-discipline of civil engineering.
Deformation Survey: a survey to determine if a structure or object is changing shape or moving. The three-dimensional positions of specific points on an object are determined, a period of time is allowed to pass, these positions are then re-measured and calculated, and a comparison between the two sets of positions is made.
Engineering Surveys: those surveys associated with the engineering design (topographic, layout and as-built) often requiring geodetic computations beyond normal civil engineering practise.
Erosion and Sediment Control Plan: a plan that is drawn in conjunction with a Subdivision Plan that denotes how upcoming construction activities will effect the movement of stormwater and sediment across the construction site and onto abutting properties and how developers will adjust grading activities to limit the depositing of more stormwater and sediment onto abutting properties than was done prior to contruction.
Foundation Survey: a survey done to collect the positional data on a foundation that has been poured and is cured. This is done to ensure that the foundation was constructed in the location authorized in the Plot Plan, Site Plan, or Subdivision Plan. When the location of the finished foundation is checked and approved the building of the remainder of the structure can commence. This should not be confused with an As-Built Survey which is not to be done until all work on the site is completed.
Hydrographic Survey: a survey conducted with the purpose of mapping the coastline and seabed for navigation, engineering, or resource management purposes. Products of such surveys are nautical charts. See hydrography.
Mortgage Survey or Physical Survey: a simple survey that generally determines land boundaries and building locations. Mortgage surveys are required by title companies and lending institutions when they provide financing to show that there are no structures encroaching on the property and that the position of structures is generally within zoning and building code requirements. Some jurisdictions allow mortgage surveys to be done to a lesser standard, however most modern U.S. state minimum standards require the same standard of care for mortgage surveys as any other survey. The resulting higher price for mortgage surveys has led some lending institutions to accept "Mortgage Inspections" not signed or sealed by a surveyor.
Plot Plan or Site Plan: a proposal plan for a construction site that include all existing and proposed conditions on a given site. The existing and proposed conditions always include structures, utilities, roadways, topography, and wetlands delienation and location if necessary. The plan might also, but not always, include hyrdology, drainage flows, endangered species habitat, FEMA Federal Flood Insurance Reference Maps and traffic patterns.
Subdivision Plan: a plot or map based on a survey of a parcel of land. Boundary lines are drawn inside the larger parcel to indicated the creation of new boundary lines and roads . The number and location of plats, or the newly created parcels, are usually discussed back and forth between the developer and the surveyor until they are agreed upon. At this point monuments, usually in the form of square concrete blocks or iron rods or pins, are driven into the ground to mark the lot corners and curve ends, and the plat is recorded in the cadastre (USA, elsewhere) or land registry (UK). In some jurisdictions, the recording or filing of a subdivision plat is highly regulated. The final map or plat becomes, in effect, a contract between the developer and the city or county, determining what can be built on the property and under what conditions. Always upon finaly completion of a subdivision an As-Built Plan is required by the local government. This is done so that the roadway constructed therein will pass ownership from the developer to said local government by way of a contract called a Covenant. When this stage is completed the roadways will now be maintained, repaved, swept, and plowed (if necessary for your geographic region) by the local government
Tape Survey: this type of survey is the most basic and inexpensive type of land survey. Popular in the middle part of the 20th century, tape surveys while being accurate for distance lack substantially in their accuracy of measuring angle and bearing. Considering that a survey is the documentation of one-half (1/2) distances and one-half (1/2) bearings this type of survey is no longer accepted amongst local, state, or federal regulatory commitees for any substaintial construction work. However for determining the extent of you property boundaries for way of peace-of-mind this type of survey is the least expensive, least time consuming and least invasive, while being no where close to accurate for the standards that are practiced by professional land surveyors.
Topographic Survey: a survey that measures the elevation of points on a particular piece of land, and presents them as contours on a plot.
Wetlands Delineation & Location Survey: a survey that is completed when construction work is to be done on or near a site containing defined wetlands. Depending on your local, state, or federal regulations wetlands are usually classified as areas that are completely inundated with water more than two (2) weeks during the growing season. Contact you local or state Conservation Commission or Wetlands Regulatory Commission to determine the particular definition for wetlands in your given geographical region. The boundary of the wetlands is determined by observing the soil colors, vegetation, erosion patterns or scour marks, hydrology, and morphology. Typically blue or pink colored flags are then placed in key locations to denote the boundary of the wetlands. A survey is done to collect the data on the locations of the placed flags and a plan is drawn to reference the boundary of the wetlands against the boundary of the surrounding plots or parcels of land and the construction work proposed within.

[edit] Surveying as a career

The basic principles of surveying have changed little over the ages, but the tools used by surveyors have evolved tremendously. Engineering, especially civil engineering, depends heavily on surveyors. Whenever there are roads, dams, retaining walls, bridges or residential areas to be built, surveyors are involved. They determine the boundaries of private property and the boundaries of various lines of political divisions. They also provide advice and data for geographical information systems (GIS), computer databases that contain data on land features and boundaries.

Surveyors must have a thorough knowledge of algebra, basic calculus, geometry, and trigonometry. They must also know the laws that deal with surveys, property, and contracts. In addition, they must be able to use delicate instruments with accuracy and precision. On the subject of accuracy, a surveyor is typically held to an accuracy standard of twelve-onethousandths (.012) (12/1000) of an inch over a length of one hundred (100) feet. This means, for perspective purposes, that a professional land surveyor can be expected to complete a survey of a one hundered (100) foot circle and upon returning to the point of beginning not deviate from his or her course no more than the width of a human finger-nail.

In most states of the U.S., surveying is recognized as a distinct profession apart from engineering. Licensing requirements vary by state, however these requirements generally all have a component of education, experience and examinations. In the past, experience gained through an apprenticeship, together with passing a series of state-administered examinations, was required to attain licensure. Nowadays, many states require a Bachelor of Science in Surveying, or a Bachelor of Science in Civil Engineering with additional coursework in surveying, in addition to experience and examination requirements. Typically the process for registration follows two phases. First, upon graduation, the candidate may be eligible to sit for the Fundamentals of Land Surveying exam, to be certified upon passing and meeting all other requirements as a Surveyor In Training (SIT). Upon being certified as an SIT, the candidate then needs to gain additional experience until he or she becomes eligible for the second phase, which typically consists of the Principles and Practice of Land Surveying exam along with a state-specific examination.

Registered surveyors usually denote themselves with the letters P.S. (professional surveyor), L.S. (land surveyor), or P.L.S. (professional land surveyor), or P.S.M. (professional surveyor and mapper) following their names, depending upon the dictates of their particular state of registration.

In Canada Land Surveyors are registered to work in their respective province. The designation for a Land Surveyor breaks down by province but follows the rule whereby the first letter indicates the province followed by L.S. There is also a designation as a C.L.S. or Canada Lands Surveyor who has the authority to work on Indian Reserves and National Parks.

Typically a licensed land surveyor is required to seal all plans, the format of which is dictated by their state jurisdiction, which shows their name and registration number. In many states, land surveyors are also required to place caps bearing their registration number on property corners that they have set.

[edit] Building Surveying

Building Surveying emerged in the 1970's as a profession in the United Kingdom by a group of technically minded General Practice Surveyors.[1] Building Surveying is a recognized profession within Britain but not widely recognized overseas although there is growth of the profession within Australia. The Services that Building Surveyors undertake are broad but include:

Construction design and building works
Project Management and monitoring
Planning Supervisor under CDM Regulations
Property Legislation adviser
Insurance assessment and claims assistance
Defect investigation and maintenance adviser
Building Surveys and measured surveys
Handling Planning applications
Building Inspection to ensure compliance with building regulations
Undertaking pre-acquisition surveys
negotiating dilapidations[2]

Building Surveyors also advise on many aspects of construction including:

design
maintenance
repair
refurbishment
restoration [3]

Clients of a building surveyor can be the public sector, Local Authorities, Government Departments as well as private sector organisations and work closely with architects, planners, homeowners and tenants groups. Building Surveyors may also be called to act as an expert witness. Building surveyors must undertake an accredited degree qualification and undertake professional training for a period of at least two years, at the end of which sit an assessment of professional competance. Professional organisations for building surveyors include CIOB and RICS.

[edit] Quantity Surveying

Quantity Surveyors play a key role in the organisation and financial management of construction projects. In essence they manage projects to ensure that they are built on time and to budget. Their job is to manage costs effectively and to ensure that they get the best value from contractors and suppliers. This involves obtaining tenders, arranging contracts and managing costs for the client while the works are undertaken. It is also their job to negotiate with the client's representative on payments and the final settlement. Quantity Surveyors deal with other professionals within their company as well as clients out-with the organisation.

It is an extremely diverse area and can include project management, facility management, construction management and management consultancy.

[edit] Land surveyor

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A land surveyor is an individual normally licensed by a State or in several States in the USA to perform the establishment or re-establishment of Land Boundaries in regards to ownership or rights in real property (land, water, mineral, easements and rights-of-way, etc.). The act of Land Surveying varies upon the requirements of the survey. In order to perform any type of a survey, the first step is always the research of the records involving the project, record title (deeds), existing easements, record survey monumentation and control (horizontal & vertical) and any available documentation from various public and private records that provide relevant data to the completion of the project. The next step in the process would ordinarily be the “field survey”, the process in which the Land Surveyor conducts a field examination of the site and gathers data generally by means of survey equipment such as a total station theodilite (loosely referred to as a transit) and a data collector (electronic data recorder), and / or GPS equipment (Global Positioning Satellites). In this process the Surveyor acquires a position on previously established survey monuments for vertical reference or for horizontal control or both. This is generally acquired in the form of coordinates (number values) such as a Northing and an Easting with X= Easting, Y= Northing, expressed as 0, 0 as the point of origin. In general terms the lower left of the project will be smaller numbers and will increase in value as the positions move to the North and to the East, beginning in the lower left of a project at 0,0 then if the next point is 300 feet to the East of this point and 200 feet to the North of this point the coordinate value is 300,200 (X=300, Y=200). The gathering of this data by RTK GPS is a direct coordinate value, by a total station theodilite requires an orientation into the system by setting up on a known point and sighting on a known point and then recording the angle between that line and the next point sighted at and then the distance to that point. The coordinate is then computed and recorded in the data collector, before data collectors the information was hand written in a “field book” and computations were performed later. After the fieldwork is gathered the next step is the analysis of the data and in a boundary survey, the completion of the fieldwork is performed by setting the permanent survey markers that control the boundary corners, then a survey plat and description (one or the other or both-depending on local and state requirements) is created and the final report is sent to be recorded (if required by law) in the appropriate government office, and a final copy is presented to the client.