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Angular Measurements And Angle Measurıng Instruments (Tacheometers And Theodolites)
CE200 SURVEYING
Associate Professor Dr. Haluk ÖZENER
Istanbul Technical University Faculty of Civil Engineering Geomatics Engineering Department
phone: 0212 2853819
e-mail: [email protected]
http://www.koeri.boun.edu.tr/jeodezi
Angles & Directions
An angle is defined as the difference in direction between two convergent lines.
A horizontal angle is formed by the directions to two objects in a horizontal plane.
A vertical angle is formed by two intersecting lines in a vertical plane, one of these lines horizontal.
A zenith angle is the complementary angle to the vertical angle and is formed by two intersecting lines in a vertical plane, one of these lines directed toward the zenith.
Angles & Directions
• Gometric Definition of AnglesA
P
B
Horizontal Angle
Vertical Angle
Angles & Directions
Vertical Angles
Tacheometers & Theodolites
Angle instruments called tacheometers or theodolites, depending on their precision in measuring angles.
EyepieceFocus(For cross hairs)
InternalFocus(For sightingobject)
Telescope clamp(up / down)
Upperplate clamp(left / right)
Slow motiontanget screw(up / down)
Slow motiontanget screw(left / right)
Axes of Theodolite
Theodolite
Theodolite
Setting up the TheodolitePlate Level Bubble Tube
Foot Screws
The bubble should be moved to the rightBubble follows direction of left thumb
Both thumbs move in (or out)
Setting up the Theodolite
Recommendations• Fine level the theodolite using the PLATE level bubble tube and foot
SCREWS
• Position a) align the plate level bubble tube with two foot screws. – Centre the bubble by rotating the two foot screws in
opposite directions. – The bubble follows the LEFT thumb.
• Position b) align the plate level bubble tube with the third foot screw.
– Centre the bubble by rotating the the third foot screw (only). The bubble follows the LEFT thumb.
Setting up the Theodolite
Position a
Bubble Follows Left Thumb
Position a Position b900 to position a
Bubble Still Follows Left Thumb
Summary Of Errors In Angle & Direction Measurements
Summary Of Errors In Angle & Direction Measurements
Summary Of Errors In Angle & Direction Measurements
Common Mistakes
Point or Target misidentificationsIncorrect recordingsImproper focusing
Officework 1
Officework 1