THEODOLITE SURVEYING PDF
THEODOLITE SURVEYING. 1 THEODOLITE. The Theodolite is a most accurate surveying instrument .. Procedure. each bisection, find the value of the angle. What is Theodolite? A surveying instrument and precision instrument for measuring angles in the horizontal and vertical planes. notes ppti.info - Download as PDF File .pdf), Text File .txt) or read online. It has wide applicality in surveying like laying of horizontal angles, locating.
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basic theodolite surveying. 1. PRESENTED BY – GROUP 5 Kailash Ayush kumar Ajit sharma Vivek maurya Sumit yadav Navneet Mahatma. The theodolite is used to measure horizontal and vertical angles. The accuracy with which It is a very important instrument in plane surveying. • Its essential. help of a theodolite, is called Theodolite surveying. .. 6) Now change the face and repeat the whole procedure to obtain the individual angle in anticlockwise.
Digital theodolites consist of a telescope that is mounted on a base, as well as an electronic readout screen that is used to display horizontal and vertical angles. Digital theodolites are convenient because the digital readouts take the place of traditional graduated circles and this creates more accurate readings. Parts of a Theodolite Like other leveling instruments, a theodolite consists of a telescope mounted on a base. The telescope has a sight on the top of it that is used to align the target.
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The instrument has a focusing knob that is used to make the object clear. The telescope contains an eyepiece that the user looks through to find the target being sighted.
An objective lens is also located on the telescope, but is on the opposite end as the eyepiece. The objective lens is used to sight the object, and with the help of the mirrors inside the telescope, allows the object to be magnified.
The theodolite's base is threaded for easy mounting on a tripod. How Does a Theodolite Work? A theodolite works by combining optical plummets or plumb bobs , a spirit bubble level , and graduated circles to find vertical and horizontal angles in surveying.
An optical plummet ensures the theodolite is placed as close to exactly vertical above the survey point. The internal spirit level makes sure the device is level to to the horizon. T-Frame or Index Bar.
Plate Levels 7. Telescope 1.
Upper tribrach has three arms, each arm carries a levelling screw for levelling the equipment. Lower tribrach has got a circular hole through which a plumb bob may be suspended for centering. Three distinct functions of levelling head are: i to support the main part of the instrument ii to attach the Theodolite to the Tripod iii to provide a means for levelling the theodolite 2.
Each degree is further divided into 10 minutes or 20 minutes. Scale plate can be clamped to any position by a clamping screw and a corresponding slow motion screw. When this is done.
The Theodolite is mounted on a tripod. This should be reasonably level and not too high nor too low for the users.
This roughly sets the theodolite optics to zero on the horizontal scale. Levelling the Theodolite. These should be used with the round spirit level to obtain a coarse adjustment. Next look at the Theodolite mounting platform. If there is not enough adjustment in the levelling screws. Align the red mark on the upper part of the theodolite with the white mark on the black ring and lock the upper horizontal clamp E.
B and C at the base of the instrument. Zero the scales Release clamps D and E. Used when measuring vertical angles. Supplies a source of light to the internal scales.
Adjust the leg lengths until it is right then screw the theodolite onto the platform. In this case.
E F G H I upper horizontal clamp and fine adjuster. Recheck the fine adjustment if necessary. You may wish to set the theodolite up over a reference point on the ground. There are 3 levelling screws labelled A. This method for levelling also applies to the EDM. A view through the small eyepiece shows the vertical and horizontal degree scales and the minutes and seconds scale.
Open the mirror H and adjust until you see a bright patch of light falling on the window underneath it. Now if you look through the small eyepiece.
Once this is done. This does not need to be true north. That is done internally and is correct if the theodolite is properly levelled Align on a reference North All your theodolite measurements are made relative to a reference baseline. From now on clamp D. There is no adjustment for vertical angles. Now clamp E.
All About Theodolites
The reading is. Look through the main eyepiece you may need to refocus and use the upper horizontal adjuster to align the vertical lines on the feature. Rotate the theodolite until the arrow in the upper or lower rough sight points to the feature of interest and lock the clamp. Movement now on the bottom plate will move the whole instrument without changing the reading. This completes the horizontal zero adjustment.
Gently lock the lower horizontal clamp D and.
To take a measurement Unlock the upper horizontal clamp E. To take the reading.
Using the minutes and seconds adjuster I set the one of the degrees on the horizontal scale so the single vertical line on the bottom scale is between the double vertical lines under the selected degree.
With the upper horizontal clamp E still on. Using the fine adjuster on the upper horizontal clamp E adjust the 0 so the single vertical line which moves with it on the bottom scale is between the double vertical lines as above as near central as possible. Once you know these. Now looking through the small eyepiece. Gently lock the clamp and use the vertical adjuster to make fine adjustments.
The reading is the degree you have aligned and the minutes and seconds read from the right hand scale.
You can easily check. If you get negative values you have to change direction.
Theodolite Survey - Civil Engineering - Lecture Slides, Slides for Civil Engineering
To use the measurement. You need to know 2 equations: To measure a vertical angle. Tripods may be telescopic.
These are distances East from the reference line and along North the reference line. To enable the tribrach to be leveled. They can also be done on hand held calculators.
The tribrach is the body of the instrument carrying ass the other parts.
You will need to join up the ends appropriately to produce the final picture. Levelling screws are fitted between the tribrach and trivet stage. If you have access to Turbocad.A double reading, micrometer type which was manufactured by the Tavistock company of London. It carries an upper clamp screw and tangent screw. They have more precise measurements, they are unaffected by wind or other weather factors, and they can be used on both flat ground and sloped ground.
In modern electronic theodolites, the spirit bubble has been replaced with an electronic one. Using the foot screws, move the optical plummet cross hairs on to the survey station. There are several moving parts and it is quite heavy. By taking precautions during the field work, it is possible to reduce their effect. Uses of Total Station 6.