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GEODESY AS A CAREER

There are many different types of careers that fall into the category of environmental sciences. Geodesy is one of them. Geodesy is the scientific discipline that deals with the measurement and representation of the Earth, including its gravitational field, in a three-dimensional time-varying space1 as well as with location of fixed points on the Earth. At one time, all work done in the field of geodesy was based on land surveys. Now, land surveys are done in conjunction with the use of satellites.

Surveying or land 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 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, engineering, trigonometry, mathematics, physics, and law. Furthermore, a particular type of surveying known as "land surveying" is the detailed study or inspection, as by gathering information through observations, measurements in the field, research of legal instruments2, and data analysis in the support of planning, designing, and establishing of property boundaries. It involves the re-establishment of cadastral surveys and land boundaries based on documents of record and historical evidence, judicial surveys, and space delineation3. Land surveying can include associated services4 such as mapping and related data accumulation, construction layout surveys5, precision measurements of length, angle, elevation, area, and volume, as well as horizontal and vertical control surveys6, and the analysis and utilization of land survey data.

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.

Surveying equipment. As late as the 1990s the basic tools used in planar surveying7 were a tape measure for determining shorter distances, a level for determining 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 position with known location and elevation, the distance and angles to the unknown point are measured. Electronic distance-measuring devices had made field surveys easier and more accurate, while much improved circle graduation has made theodolites (transists) lighter as well as more precise. 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 stations8 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), a device used to help define a location and map it in relation to other spots on the planet. This is something that can be quite useful to geodesists who use GPS in their field of work. With the use of a GPS device, geodesists can locate the exact position of any object on the surface of Earth which gives them valuable information without the need to physically travel to locate or chart specific things. Though real-time kinematic GPS systems have increased the speed of surveying, they are still only horizontally accurate to about 20 mm and vertically accurate to about 30-40 mm. However, GPS systems do not work well in areas with dense tree cover or constructions. Total stations are still used widely, along with other types of surveying instruments. One-person robotic-guided total stations9 allow surveyors to gather precise measurements without extra workers to look through and turn the telescope or record data. A faster way to measure large areas (not details, and no obstacles) is with a helicopter, equipped with a laser scanner, combined with a GPS to determine the position and elevation of the helicopter. To increase precision, beacons are placed on the ground (about 20 km apart). This method reaches precisions between 5-40 cm (depending on the flight height).

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, railways, reservoir, dams, bridges or residential areas to be built, surveyors are involved. They establish the boundaries of legal descriptions 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 features10 and boundaries. A geographic information system (GIS) is any system that captures, stores, analyzes, manages, and presents data that are linked to location. In the simplest terms, GIS is the merging of cartography and database technology. GIS systems are used in cartography, remote sensing, land surveying, photogrammetry, geography, urban planning, emergency management11, navigation, and localized search engines12. In the strictest sense, the term describes any information system that integrates, stores, edits, analyzes, shares, and displays geographic information. In a more generic sense, GIS applications are tools that allow users to create interactive queries (user-created searches)13, analyze spatial information, edit data, maps, and present the results of all these operations. 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 precision14.

What does a geodesist do? A geodesist measures the Earth's surface. He studies the science and shape of our planet as well as its gravitational field. A geodesist measures the size of the Earth on a global scale and also specific regions of land known as fixed points. By doing so, crustal shifts and polar movement can be detected. Measurements can determine rate of movement and other pertinent information. A geodesist assigns 3 dimensional points on, above and below the surface of the Earth to measure the average depths of oceans, mountain peaks and also abnormalities in the surface of the Earth. The field of geodesy also includes the study of tides as well as crustal and polar motion15. The field of geodesy developed from the human need to understand the world in which we live. As it was once believed that our world was flat, we now know much more about our planet through specialized fields such as geodesy.

 

Notes:

 

1 …in a three-dimensional time-varying space…   2 …research of legal instruments… 3 …space delineation 4 …associated services… 5 …construction layout surveys… 6 …horizontal and vertical control surveys… 7 …planar surveying… 8 …top-of-the-line total stations… 9 one-person robotic-guided total stations…   10 …land features… 11 …emergency management… 12 …localized search engines 13 …interactive queries (user-created searches)… 14 …delicate instruments with accuracy and precision 15 …crustal and polar motion – в постоянно изменяющемся во времени трехмерном пространстве – изучение юридической документации – обозначение границ – сопутствующие виды деятельности – геодезические разбивочные работы – съемки планового и высотного обоснований – плановая съемка – новейшие (самые современные) тахеометры – автоматизированные электронные тахеометры, управляемые одним оператором – особенности рельефа – служба скорой помощи – местные системы поиска – интерактивное общение с пользователем – высокоточные приборы, требующие аккуратного (острожного) обращения – движение земной коры и полюсов

 

Word list

 

accuracy accurate applicable   apply average beacon boundary capture delineation electronic distance measurement device (EDM) elevation engineering evidence evolve execution exact feature   field   global positioning system judicial land surveying   level   locate   merging objective observation – точность, аккуратность – точный, аккуратный – применяемый, приемлемый – применять – средний – геодезический знак – граница – захват –очертание, изображение – электронные приборы для определения расстояния – высота, превышение – строительство – доказательство – развиваться – исполнение – точный – особенность, характерная черта – поле, сфера деятельности – система глобального позиционирования – юридический – земельная съёмка, наземная съёмка – уровень, нивелир; ровный – определять местоположение – слияние – цель – наблюдение obstacle onboard computer ownership pertinent   positioning   precise property quiery, n quiery, v remote sensing   satellite positioning system shift   software spatial spot surface survey   surveying surveyor tape terrestrial theodolite tide total station triangulation tripod vertical control urban planning – препятствие – встроенный (бортовой) компьютер – собственность – подходящий, соответствующий – позиционирование, определение положения – точный – собственность, имущество – вопрос – спрашивать, осведомлять – дистанционное зондирование – спутниковая система позиционирования – сдвиг, перемещение, изменение – программное обеспечение – пространственный – место, пятно – поверхность – съёмка, производить съёмку – съёмка, геодезия – геодезист, топограф – мерная лента – наземный – теодолит – прилив, отлив – электронный тахеометр – триангуляция – тринога, штатиф – высотное обоснование – городское планирование

 

 

Exercises





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