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Fundamentals of surveying in explain their theory and samples of excercises written by Dr. Yuji Murayama from university of Tsukuba.
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Prof. Dr. Yuji Murayama Surantha Dassanayake
In a right triangle, the square of the hypotenuse is equal to the sum of the squares of the other two sides. C 2 = A^2 + B^2 where: C is the hypotenuse (side opposite the right angle). A and B are the remaining sides.
1 circle = 360° = 21,600´ = 1,296,000˝ 1° = 60´ = 3600˝ 1´ = 60˝ Basic Trigonometry functions for Distance and Angular Measurements
Using the definitions on the previous page, we can determine the values of the functions for each angle shown below. List the Sine, Cosine, and Tangent of each angle in both fractional and
English mathematician Edmund Gunter (1581-1626) gave to the world not only the words cosine and cotangent, and the discovery of magnetic variation, but the measuring device called the Gunter’s chain shown below. Edmund also gave us the acre which is 10 square chains. The Gunter’s chain is 1/80th of a mile or 66 feet long. It is composed of 100 links, with a link being 0.66 feet or 7. inches long. Each link is a steel rod bent into a tight loop on each end and connected to the next link with a small steel ring. Starting in the early 1900’s surveyors started using steel tapes to measure distances. These devices are still called “chains” to this day.
In the early 1950’s the first Electronic Distance Measuring (EDM) equipment were developed. These primarily consisted of electro-optical (light waves) and electromagnetic (microwave) instruments. They were bulky, heavy and expensive. The typical EDM today uses the electro-optical principle. They are small, reasonably light weight, highly accurate, but still expensive.
A Theodolite is a precision surveying instrument; consisting of an alidade with a telescope and an accurately graduated circle; and equipped with the necessary levels and optical-reading circles. The glass horizontal and vertical circles, optical-reading system, and all mechanical parts are enclosed in an alidade section along with 3 leveling screws contained in a detachable base or tribrach. A Transit is a surveying instrument having a horizontal circle divided into degrees, minutes, and seconds. It has a vertical circle or arc. Transits are used to measure horizontal and vertical angles. The graduated circles (plates) are on the outside of the instrument
The Relative directions of lines connecting survey points may be obtained in a variety of ways. The figure below on the left shows lines intersecting at a point. The direction of any line with respect to an adjacent line is given by the horizontal angle between the 2 lines and the direction of rotation. The figure on the right shows the same system of lines but with all the angles measured from a line of reference (O-M). The direction of any line with respect to the line of reference is given by the angle between the lines and its direction of rotation.
In plane surveys it is convenient to perform the work in a rectangular XY coordinate system in which one central meridian coincides with a true meridian. All remaining meridians are parallel to this central true meridian. This eliminates the need to calculate the convergence of meridians when determining positions of points in the system. The methods of plane surveying, assume that all measurements are projected to a horizontal plane and that all meridians are parallel straight lines. These are known as grid meridians. The Oregon Coordinate System is a grid system. On certain types of localized surveying, it may not be necessary to establish a true, magnetic, or grid direction. However it is usually desirable to have some basis for establishing relative directions within the current survey. This may be done by establishing an assumed meridian. An assumed meridian is an arbitrary direction assigned to some line in the survey from which all other lines are referenced. This could be a line between two property monuments, the centerline of a tangent piece of roadway, or even the line between two points set for that purpose. The important point to remember about assumed meridians is that they have no relationship to any other meridian and thus the survey cannot be readily (if at all) related to other surveys Assumed Meridians
The azimuth of a line on the ground is its horizontal angle measured from the meridian to the line. Azimuth gives the direction of the line with respect to the meridian. It is usually measured in a clockwise direction with respect to either the north meridian or the south meridian. In plane surveying, azimuths are generally measured from the north. When using azimuths, one needs to designate whether the azimuth is from the north or the south. Azimuths are called true (astronomical) azimuths, magnetic azimuths, grid azimuths, or assumed azimuths depending on the type of meridian referenced. Azimuths may have values between 0 and 360 degrees.
Using angles to the right, calculate the bearings and azimuths of each lines.
Another way of describing the position of point P is by its distance r from a fixed point O and the angle θ that makes with a fixed indefinite line oa (the initial line). The ordered pair of numbers (r,θ) are called the polar coordinates of P. r is the radius vector of P and θ its vectorial angle. Note: (r,θ), (r, θ + 360o), (-r, θ + 180o) represent the same point. Transformation of Polar and Rectangular coordinates: Measuring distance between coordinates When determining the distance between any two points in a rectangular coordinate system, the pythagorean theorem may be used. In the figure below, the distance between A and B can be computed in the following way :
Area of a trapezoid: one-half the sum of the bases times the altitude. Area of a triangle: one-half the product of the base and the altitude. The area enclosed within a figure can be computed by coordinates. This is done by forming trapezoids and determining their areas. Trapezoids are formed by the abscissas of the corners. Ordinates at the corners provide the altitudes of the trapezoids. A sketch of the figure will aid in the computations.