MAD 256 SURVEYING INTRODUCTION UNITS SIGNIFICANT FIGURES MARCH. Güneş Ertunç, PhD Assist. Prof

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1 MAD 256 SURVEYING MARCH 5 INTRODUCTION UNITS SIGNIFICANT FIGURES Güneş Ertunç, PhD Assist. Prof gertunc@hacettepe.edu.tr

2 MAD 256 SURVEYING MARCH 5 MARCH 12 MARCH 19 MARCH 26 APRIL 2 APRIL 9 INTRODUCTION, UNITS AND SIGNIFICANT FIGURES THEORY OF ERRORS IN OBSERVATIONS LEVELING THEORY, METHODS, AND EQUIPMENT DISTANCE MEASUREMENT ANGLES, AZIMUTHS, AND BEARINGS MIDTERM I yunus.hacettepe.edu.tr/~gertunc

3 MAD 256 SURVEYING APRIL 16 APRIL 23 APRIL 30 MAY 7 MAY 14 MAY 21 MAY 28 TOTAL STATION INSTRUMENTS National Sovereignty and Children's Day AREA MAPPING MAPPING 2 MIDTERM II COURSE REVIEW

4 MAD 256 SURVEYING A surveyor is a professional person with the academic qualifications and technical expertise to conduct the following activities; to determine, measure and represent the land, three-dimensional objects, point-fields, and trajectories; to assemble and interpret land and geographically related information;

5 MAD 256 SURVEYING A surveyor is a professional person with the academic qualifications and technical expertise to conduct the following activities; to use that information for the planning and efficient administration of the land, the sea and any structures to conduct research into the above practices and to develop them.

6 MAD 256 SURVEYING

7 MAD 256 SURVEYING It is strongly recommended for you to carry these items with you at all times. - Scientific calculator, - A ruler - milimetric paper (A4) - Protractor (degree-grad)

8 Z A J N B L

9 Zenith direction CASE 1 Horizontal Direction Elevation angle Depression angle Zenith angle Nadir angle CASE 2 Nadir direction

10 Vertical Angles ALN JLB A J N B L

11 Zenith Angle Z ZLA ZLJ ZLN ZLB N A J B L

16 UNITS The metric system was originally developed in the 1790s in France. Although other definitions were suggested at that time, the French Academy of Sciences chose to define the meter as 1/10,000,000 of the length of the Earth s meridian through Paris from the equator to the pole. The meter is the basic unit for length in the metric or SI system. Subdivisions of the meter (m) are the millimeter (mm), centimeter (cm), and decimeter (dm), equal to 0.001, 0.01, and 0.1 m, respectively. A kilometer (km) equals 1000 m, which is approximately five eighths of a mile.

17 UNITS Areas in the metric system are specified using the square meter (m 2 ). Large areas, for example, tracts of land, are given in hectares (ha), where one hectare is equivalent to a square having sides of 100 m. Thus, there are 10,000 m 2, or about acres per hectare. The cubic meter (m 3 ) is used for volumes in the SI system. Degrees, minutes, and seconds, or the radian, are accepted SI units for angles.

18 SIGNIFICANT FIGURES A distance measured with a tape whose smallest graduation is 0.01 m, and recorded as m, is said to have four significant figures; in this case the first three digits are certain, and the last is rounded off and therefore questionable but still significant.

19 SIGNIFICANT FIGURES Two significant figures: 24, 2.4, 0.24, , Three significant figures: 364, 36.4, , Four significant figures: 7621, 76.21, , 24.00

20 SIGNIFICANT FIGURES Addition or subtraction: 1. Identify the column containing the rightmost significant digit in each number being added or subtracted 2. Perform the addition or subtraction, 3. Round the answer so that its rightmost significant digit occurs in the left- most column identified in step (1).

21 SIGNIFICANT FIGURES (correct) (correct)

22 SIGNIFICANT FIGURES In multiplication, the number of significant figures in the answer is equal to the least number of significant figures in any of the factors. For example, x 2.13 = when multiplied, but the answer is correctly given as 772. Its three significant figures are governed by the three significant digits in 2.13

23 SIGNIFICANT FIGURES Likewise, in division the quotient should be rounded off to contain only as many significant figures as the least number of significant figures in either the divisor or the dividend

24 SIGNIFICANT FIGURES Rounding off a number is the process of dropping one or more digits so the answer contains only those digits that are significant.

25 SIGNIFICANT FIGURES 1. When the digit to be dropped is lower than 5,the number is written without the digit. Thus, becomes Also rounded to four figures becomes When the digit to be dropped is exactly 5,the nearest even number is used for the preceding digit. Thus, becomes and is also rounded to When the digit to be dropped is greater than 5,the number is written with the preceding digit increased by 1. Thus, becomes 78.39

26 SIGNIFICANT FIGURES It is important to recognize that rounding should only occur with the final answer. Intermediate computations should be done without rounding to avoid problems that can be caused by rounding too early (correct) (incorrect)

27 QUESTIONS Convert the following distances given in feet to meters: a) ft b) ft c) ft

28 QUESTIONS What are the radian and degree minute second equivalents for the following angles given in grads: a) grads b) grads c) grads

29 QUESTIONS Convert the adjusted angles of a triangle to radians and show a computational check: a) b) c) d) e) f)

Introduction to Measurements. Introduction to Measurements. Introduction to Measurements. Introduction to Measurements. Introduction to Measurements

Introduction to Measurements. Introduction to Measurements. Introduction to Measurements. Introduction to Measurements. Introduction to Measurements CIVL 1112 Surveying - Precision and 1/8 Typically, we are accustomed to counting but not measuring. Engineers are concerned with distances, elevations, volumes, direction, and weights. Fundamental principle