Fore bearing and back bearing in surveying pdf

Reduced bearing rb or quadrantal bearing qb fore bearing fb or forward bearing fb back bearing or backward bearing bb calculated bearing. Back bearing bearing measured opposite to the direction of survey in the figure below, oa is the survey line to be set out. Prismatic compass surveying pdf notes download compass surveying prismatic compass compass traversing important definition true meridian. B fore bearing is the bearing of the line in the forward direction of surveying. Fore bearing and back bearing is explained with solved examples from previous year competitive exams like gate, ies. Add or subtract 180 from you forward bearing to get your back bearing.

February 24, 2017 nomenclature of building parts and planning february 23, 2017. The direction of a survey line can either be established with relation to each other or with relation to any meridian. Back bearing the bearing of a line measured in the backward direction is. Surveying is a science as well as an art, by which studies are made of the objects present on the ground and below the ground at different points. Angles and directions in surveying, the direction of a line is described by the horizontal angle that it makes with a. Aait, department of civil engineering 2 lecture note. Similarly from the fig 4, the fore bearing is of the line cd is s. You want the result to fall between 0 and 360, so if the forward bearing is less than 180, add 180 to it, and if its greater than 180, subtract 180. What is fore bearing and back bearing in surveying. Following readings were taken in a closed traverse.

The formula used to calculate the fore bearing of the progressive line f. Also, local attraction is explained which often is asked in exams. Type a the summation of entire included angle is equal to 2n4 x 900. Fore bearing and back bearing confusion, please help.

Calculation of angles from bearings compass surveying. It is the angle measured from the next station point to the previous station point from which the fore bearing is determined. It is not possible to check the consistence of angles and distance measurement. In civil engineeringsurveying, bearing is the process to get the direction of a survey line. As shown in fig4 above, the bearing taken in the direction of ab is called as fore bearing and the measurement taken in the direction of ba forms the back bearing as shown in the figure4. When the magnetic needle is suspended freely and balanced properly. The principle of compass surveying is traversing, which involves a series of connected lines. Temporary adjustments in compass survey using a prismatic compass. The bearing of a line is measured in the direction opposite to the survey is called the back bearing of the bb line. The magnetic bearings of the lines are measured by prismatic compass and the distances of the lines are measured by chain. Surveying civil engineering objective questions and. The angle bac can then be obtained by the application of the above rule.

The first compass bearing we need to take at the lake is from our unknown location to our cabin on the far shore. It is the angle which is measured directly from the survey station point and other station in the same path of conduct of survey. What is fore bearing and back bearing in surveying with examples duration. Direction of survey and location of the north however guides the relation between back bearing and fore bearing based on the reference point. Prismatic compass surveying pdf notes expert civil. Both bearings and azimuths refer to the relationship of the given line to a reference meridian, usually one of many interpretations of north. Similarly from the next figure, the fore bearing of line cd is s. In many applications, including descriptions, plats, and maps, the direction of a given line is expressed as a bearing or azimuth. The definition of the whole circle bearing along with the measuring formula and example is discussed below. The angle made by the survey line with reference to arbitrary meridian is known as arbitrary bearing. It is a point on which fore sights and backsight are taken. It starts at a point of known position and terminates at a point of unknown position. Civil engineeringsurveying and leveling 362 important mcq pdf.

Home mcq surveying surveying civil engineering objective questions and answers set 01 surveying civil engineering objective questions and answers set 01 mcq surveying edit practice test. As the name indicates, quadrantal bearing depends upon the quadratic position of a line. Quadrantal bearing reduced bearing surveying civil. The bearing we end up with represents the angle between a line from magnetic north to our location, and a line from our. Classification of bearings surveying civil engineering. The bearing of a line is measured in the direction of the progress of the survey is called the fore bearing of the fb line. While setting out a survey line, the bearing readings are necessary fore bearing bearing measured in the direction of progress of survey. Basic surveying theory and practice for performing certain mathematical operations with angles, it is sometimes easier to convert to decimal degrees first, perform the necessary math, then convert back to degrees, minutes, and seconds. Local attraction at a place can be detected by observing bearings from both ends of the line in the area. Check the accuracy of your calculations by reversing them.

Fore bearing fore bearing the bearing of a line measured in the forward direction i. Back bearing bb the bearings measured in opposite to the progress of surveying i. Add 180 degrees to the compass bearing to your destination if the bearing is less than 180 degrees. Understanding forward and back bearings taking a forward bearing. The bearing of the line in the direction of progress of survey is called fore or forward bearing while the bearing opposite to the direction of. It is the bearing of the survey line taken from the forward survey station to the preceding station from which the fore bearing was taken earlier. A prismatic compass is a navigation and surveying instrument which is extensively used to find out the bearing of the traversing and included angles between them, waypoints an endpoint of the lcourse and direction. In figure, if the bearing of same line ab is measured from b towards a, it is known as backward bearing or back bearing.

Compass surveying is a type of surveying in which the directions of surveying lines are determined with a magnetic compass, and the length of the surveying lines. Fore and back bearing a line may be expressed by two bearings observed from the either end of the line. In traversing with a compass free or loose needle method is employed to determine direction of survey line. Bearing fore bearing fb the bearings measured in the progress of surveying i. This concept is applicable in surveying field of study. Type b when the summation of entire included angle is not equal to 2n4 x 900. The quadrantal bearing is a common notation system of bearings. Thus it can be staled that to convert the fore bearing to back bearing it is only necessary to change the cardinal points by substituting n for s, and e.

Bcn 4030 w the magnetic bearing of a line ab is 530 what will be the true bearing, if the declination is 515 w. Below are the bearings observed in a traverse survey conducted with a prismatic compass at a place. Thus, it can be stated that to convert the fore bearing to back bearing. In this post, we are going to discuss about the bearing in surveying and its designation. Basic surveying 15cv34 department of civil engg, ace page 41 fore bearing and back bearing difference will be 1800. Fore bearing of a line is horizontal angle in the direction of progress of survey. Fore bearing fb the bearings measured in the progress of surveying i.

The use of levels and total stations is illustrated by a series of practical examples. The fore bearing and back bearing conducted on a line ab. In civil engineering surveying, bearing is very important to get the direction of a survey line. Then, starting from this adjusted line, the fore and back bearing of other lines are corrected. Surveying which involves series of connected lines is known as traversing the sides of traverse are known is known as traverse legs. Civil engineering assignment help, survey, what is fore bearing and back bearing.