Sources of error in leveling
- seotskpak
- Nov 28, 2016
- 2 min read
The following are different sources of error in leveling. Instrumental errors; The permanent adjustment of the instrument may not be perfect. That is, the line of collimation, may not be parallel to axis of the bubble tube. The internal arrangement of the focusing tube is not perfect. The graduation of the leveling staff may not be perfect. Personal errors The instrument may not be leveled perfectly. The focusing of the eye piece and object glass may not be perfect and the parallax may not be eliminated entirely. Technical Data used in the field explained in civil surveyor course in rawalpindi. The position of the staff may be displayed at the change point at the time of taking FS and BS readings.
The staff may appear inverted when viewed through the telescope. By mistake, the staff readings may be taken upwards instead of downwards. The reading of the stadia hair rather than the central collimation hair may be taken by mistake. A wrong entry may be made in the level book. The staff may not be properly and fully extended. Error due to natural causes ; when the distance of sight is long, the curvature of the earth may affect the staff reading. Some more details of civil surveyor course in rawalpindi are as under. The effect of refraction may cause a wrong staff reading to be taken. The effect of high winds and a shining sun may result in a wrong staff reading.
Permissible error in leveling;
The precision of leveling is ascertained according to the error of closure. The permissible limit of closing error depends upon the nature of work for which the leveling is to be done. Permissible closing error is expressed as E= C D E= Closing error in meters C= the constant D= distance in kilometers. The following are the permissible errors for different types of leveling. Rough leveling – E = + 0.100D Ordinary leveling – E = +0.025 D Accurate leveling – E = + 0.012 D Precise leveling- E = + 0.006 D. TSK Training for Skills and Knowledge is the best institute in Rawalpindi Islamabad for Pakistani Students who wants to join civil surveyor course in islamabad.
Comments