konechny_variant_metodichki АНГЛИЙСКИЙЙ. Методическое пособие по английскому языку Подписано в печать Формат

2. 
   Read and translate the text:
   

Geodesy

Geodesy, also called geodetics, is the scientific discipline that deals with the measurement and representation of the Earth, its gravitational field and geodynamic phenomena (polar motion, earth tides, and crustal motion) in three-dimensional time space.

Geodesy is primarily concerned with positioning and the gravity field and geometrical aspects of their temporal variations, although it can also include the study of the Earth's magnetic field.

Geodesy may be divided into the areas of global geodesy, national geodetic surveys, and plane surveying. Global geodesy is responsible for the determination of the figure of the Earth and of the external gravity field. A geodetic survey establishes the fundamentals for the determination of the surface and gravity field of a country. This is realized by coordinates and gravity values of a sufficiently large number of control points, arranged in geodetic and gravimetric networks. In this fundamental work, curvature and the gravity field of the earth must be considered. In plane surveying (topographic surveying, cadastral surveying, engineering surveying) the details of the terrain are obtained. In plane surveying the horizontal plane is generally sufficient.

There is close cooperation between global geodesy, geodetic surveying and plane surveying. The geodetic survey adopts the parameters determined by measurements of the earth, and its own results are available to those who measure the earth. The plane surveys, in turn, are generally tied to the control points of the geodetic surveys and serve then particularly in the development of national map series and in the formation of real estate cadastres. Measurement and evaluation methods are largely identical in global geodesy and national geodetic surveys. Particularly space methods (satellite geodesy) enter more and more into regional and even local surveys. This also implies more detailed gravity field determination on regional and local scale.
3.Answer the following questions:

1. 
   What does geodesy deal with?
   
2. 
   What are the main sections of geodesy?
   
3. 
   What is global geodesy responsible for?
   
4. 
   What science establishes the fundamentals for the determination of the surface and gravity field of a country? How is it realized?
   
5. 
   What are the main subdivisions of plane surveying?
   
6. 
   Are there close cooperation between global geodesy, geodetic surveying and plane surveying? Why?
   

Text 2

1. 
   Read and translate the text:
   

Alexander Ross Clarke

A.R.Clarke (1828 – 1914) was an English geodesist whose calculations of the size and shape of the Earth were the first to approximate accepted modern values with respect to both polar flattening and equatorial radius. The figures from his second determination (1866) became a standard reference for U.S. geodesy, even after the acceptance of other figures by the International Union of Geodesy and Geophysics in 1924.

Appointed to the Royal Engineers (1847), Clarke remained with the British ordnance survey at Southampton from 1850 to 1881. He was responsible for the principal triangulation (long-distance trigonometric surveying) of the British Isles and published the results of the first geodetic survey of Great Britain in 1861. Entrusted with comparing the standards of length for measuring an international arc of triangulation from Ireland to Russia, he published his results in 1866. His Geodesy (1880) has remained one of the best textbooks on the subject.

2. 
   Find information about other Russian and foreign geodesists. Get ready to tell this information in the classroom. Use in your speech different general formulas such as:
   

Text 3

1. 
   Read and translate the text:
   

Methods of Geodesy

Until the advent of satellites, all geodesic work was based on land surveys made by methods employing a geodesic coordinate system.

Triangulation in navigation, surveying, and civil engineering, is a technique for precise determination of distances and angles for location of a ship’s or aircraft’s position, and in such attempts as road building, tunnel alignment, and other construction. It is based on the laws of plane trigonometry, that if one side and two angles are known, the other two sides and angle can be readily calculated. One side of the selected triangle is measured. This is the baseline. The two adjacent angles are measured by means of a surveying device known as a theodolite, and the entire triangle is established. By constructing a series of such triangles, each adjacent to at least one other, values can be obtained for distances and angles not otherwise measurable. Triangulation points are usually placed on the tops of the hills because the neighbouring points must be clearly visible.

Triangulation was used by the ancient Egyptians, Greeks, and other peoples at a very early date, with crude sighting devices that were improved into the diopter (an early theodolite) in the 1^st century AD by Hero of Alexandria.

Trilateration is a method of surveying in which the lengths of the sides of a triangle are measured, usually by electronic means, and from this information, angles are computed. By constructing a series of triangles, adjacent to one another, a surveyor can obtain other distances and angles. Formerly, trilateration was little used in comparison to triangulation, because of the difficulty of the computations involved. But the development of electronic distance-measuring devices has made trilateration a common and preferred system.

2. 
   Answer the questions:
   

1. 
   What was all geodesic work based until the advent of satellites on?
   
2. 
   What are the main geodetic methods used nowadays?
   
3. 
   What is the main principle of triangulation?
   
4. 
   When and where was triangulation introduced?
   
5. 
   Where are usually triangulation points placed on? Why?
   
6. 
   What is the main idea of trilateration?
   
7. 
   How can a surveyor obtain distances and angles using this method?
   

3. 
   Complete the sentences:
   

1. 
   Triangulation is a technique for...
   
2. 
   Triangulation is based on the laws of plane trigonometry, that if...
   
3. 
   Triangulation points are usually placed on the …
   
4. 
   Triangulation was used by …
   
5. 
   Trilateration is a method of ...
   
6. 
   A surveyor can obtain other distances and angles by …
   
7. 
   Trilateration was little used in comparison to triangulation, because …
   
8. 
   … has made trilateration a common system.
   

Text 4

1. 
   Read and translate the text:
   

Introduction of Triangulation

The idea of triangulation was apparently conceived by the Danish astronomer Tycho Brache before the end of the 16^th century, but it was developed as a science by a contemporary Dutch mathematician Willebroad van Roijen Snell. He used a chain of 33 triangles to determine the length of an arc essentially in the way customarily done today. The resulting size of the Earth, however, was 3.4 percent too small.

In 1669 Jean Picard, a French astronomer, first used a telescope in determining latitude and in measuring angles in triangulation that consisted of 13 triangles and extended from Paris to 1.2˚ northward. His observations and results were extremely important because his length of arc was used by the English physicist and mathematician Sir Isaac Newton in his theoretical calculations to prove that the attraction of the Earth is the principal force governing the motion of the moon in its orbit.

2. 
   Find information about other geodetic methods such as traversing, leveling and radiation. Discuss in groups the key features of these methods.
   

Text 5

The Main Geodetic Concepts

1. 
   Make word combinations and translate them:
   

2. 
   Read and translate the text:
   

Here we define some basic observational concepts, like angles and coordinates, defined in geodesy (and astronomy as well), mostly from the viewpoint of the local observer.

• 
  The plumb-line or vertical is the direction of local gravity, or the line that results by following it.
  
• 
  The zenith is the point on the celestial sphere where the direction of the gravity vector in a point, extended upwards, intersects it.
  
• 
  The nadir is the opposite point, where the direction of gravity extended downward intersects the (invisible) celestial sphere.
  
• 
  The celestial horizon is a plane perpendicular to a point's gravity vector.
  
• 
  Azimuth is the direction angle within the plane of the horizon, typically counted clockwise from the north or south.
  
• 
  Elevation is the angular height of an object above the horizon.
  
• 
  Local topocentric coordinates are azimuth (direction angle within the plane of the horizon) and elevation angle (or zenith angle) and distance.
  
• 
  The north celestial pole is the extension of the Earth's (precessing and nutating) instantaneous spin axis extended northward to intersect the celestial sphere (similarly for the south celestial pole).
  
• 
  The celestial equator is the intersection of the (instantaneous) Earth equatorial plane with the celestial sphere.
  
• 
  A meridian plane is any plane perpendicular to the celestial equator and containing the celestial poles.
  
• 
  The local meridianis the plane containing the direction to the zenith and the direction to the celestial pole.
  

3. 
   Answer the questions:
   

1. 
   What are the main geodetic concepts?
   
2. 
   Give definitions to the main geodetic concepts.
   

Text 6

1. 
   Read and translate the text:
   

Geodetic Observing Instruments

Some of the most important geodetic instruments are the surveyor’s level, the theodolite and the tacheometer (or total station).

The surveyor’s level is used in surveying to measure the height of distant points in relation to some datum (usually, mean sea level). It consists of a telescope fitted with a spirit level and, generally, mounted on a tripod. It is used in conjunction with a graduated rod placed at the point to be measured and sighted through the telescope.

Here are the main steps in using the surveyor’s level:

Step 1: Find a reference point (benchmark elevation)

Step 2: Set up the surveyor's level

Step 3: Reading the leveling rod

Step 4: Taking readings

Step 5: Make a grid over the chosen plot

Step 6: Making sense of the collected data

Step 7: Drawing topography lines

The theodolite is a basic surveying instrument of unknown origin but going back to the 16^th-century English mathematician Leonard Digges. It is used to measure horizontal and vertical angles. In its modern form it consists of a telescope mounted to swivel both horizontally and vertically. Leveling is accomplished with the aid of a spirit level; crosshairs in the telescope permit accurate alignment with the object sighted. After the telescope is adjusted precisely, the two accompanying scales, vertical and horizontal, are read. Mounted on a tripod with adjustable legs, the theodolite is used in the field to obtain precise angular measurements for triangulation in road building, tunnel alignment, and other engineering work. The transit is a variety of theodolite that has a telescope so mounted that it can be completely reversed, or transited. The phototheodolite, a combination camera and theodolite mounted on the same tripod, is used in terrestrial photogrammetry for mapmaking and other purposes.

The tacheometer additionally determines, electronically or electro-optically, the distance to target, and is highly automated in its operations.

2. 
   Answer the following questions:
   

1. 
   What are the main geodetic instruments?
   
2. 
   What is the surveyor’s level used for?
   
3. 
   What does the level consist of?
   
4. 
   Name the main steps in using the level.
   
5. 
   When and by whom was the theodolite invented?
   
6. 
   What are the theodolites used for?
   
7. 
   What does the theodolite consist of?
   
8. 
   What varieties of the theodolite are there?
   
9. 
   What does the tacheometer determine?
   

3. 
   Look at the picture below. Name the main parts of a theodolite. Translate into Russian.
   

4. 
   Fill the table with the information from the picture:
   

Part of the theodolite	Its function

  1   2   3   4   5   6   7   8