Surveying and Total Station
SURVEYING
LEVELLING
Levelling is the branch of surveying the object of which is : 1. To find the elevations of the given points with respect to a given or assumed datum, and 2. To establish points at a given elevations or at different elevations with respect to a given or assumed datum. The operation is required in the setting out of all kind of engineering works. levelling deals with measurements in a vertical plane.
MEATHODS OF LEVELLING
Three principal methods are used for determining difference in elevations, namely, barometric levelling, trigonometric levelling, and spirit levelling.
LEVELLING INSTRUMENTS
The instruments commonly used in direct levelling are : 1. A level 2. A levelling staff
1.LEVEL
The purpose of a level is to provide horizontal sight. Essentially, a level consists of the following four parts : a. A telescope to provide line of sight. b. A level tube to make the line of site horizontal. c. A levelling head (tribrach or trivet stage) to bring the bubble its centre of run. d. A tripod to support the instrument.
AUTO LEVEL An Auto Level machine is the equipment used for all surveying and engineering level applications. They are suitable for obtaining accurate levels during surveys even if the ground is not levelled. For this, an automatic level comes complete with an internal compensator mechanism which is a swinging prism. When this mechanism is set close to level, it automatically removes any remaining variation from level. This reduces the requirement to set the instrument truly level even when it is a dumpy or tilting level. It is, therefore, a self-levelling instruments designed by auto level manufacturers for accuracy, ease of operation and rugged dependability. Auto level is now the preferred instrument on building sites, construction and surveying due to ease of use and rapid setup time. They also give maximum portability. Most of the auto levels are supplied with alumnium telescopic tripod
LEVELLING
Levelling is the branch of surveying the object of which is : 1. To find the elevations of the given points with respect to a given or assumed datum, and 2. To establish points at a given elevations or at different elevations with respect to a given or assumed datum. The operation is required in the setting out of all kind of engineering works. levelling deals with measurements in a vertical plane.
MEATHODS OF LEVELLING
Three principal methods are used for determining difference in elevations, namely, barometric levelling, trigonometric levelling, and spirit levelling.
LEVELLING INSTRUMENTS
The instruments commonly used in direct levelling are : 1. A level 2. A levelling staff
1.LEVEL
The purpose of a level is to provide horizontal sight. Essentially, a level consists of the following four parts : a. A telescope to provide line of sight. b. A level tube to make the line of site horizontal. c. A levelling head (tribrach or trivet stage) to bring the bubble its centre of run. d. A tripod to support the instrument.
AUTO LEVEL An Auto Level machine is the equipment used for all surveying and engineering level applications. They are suitable for obtaining accurate levels during surveys even if the ground is not levelled. For this, an automatic level comes complete with an internal compensator mechanism which is a swinging prism. When this mechanism is set close to level, it automatically removes any remaining variation from level. This reduces the requirement to set the instrument truly level even when it is a dumpy or tilting level. It is, therefore, a self-levelling instruments designed by auto level manufacturers for accuracy, ease of operation and rugged dependability. Auto level is now the preferred instrument on building sites, construction and surveying due to ease of use and rapid setup time. They also give maximum portability. Most of the auto levels are supplied with alumnium telescopic tripod