Preparing to measure
Setting up the total station over a ground point
1.Place the tripod approximately over the ground
point.
2.Inspect the tripod from
various sides and correct
its position so that the
tripod plate is roughly
horizontal and above the
ground point (illustration,
top left).
3.Push the tripod legs
firmly into the ground
and use the central fixing
screw to secure the
instrument on the tripod.
4.Switch on the laser
plummet (or, for older
instruments, look
through the optical
plummet) and turn the
foot screws so that the
laser dot or the optical
plummet is centered on
the ground point
(illustration, top right).
5. Center the bull’s-eye
bubble by adjusting the
lengths of the tripod legs
(illustration below).
6.After accurately leveling
up the instrument, release the central fixing
screw so that you can
displace it on the tripod
plate until the laser dot
is centered precisely over
the ground point.
7.Tighten the central fixing
screw again.
Measuring with the level
Measuring distances optically
with the level
Line levelling
If the points A and B are widely separated, the height difference between them is determined by line levelling with target distances generally between 30 and 50 metres. Pace out the distances between the instrument and the two staffs; they need to be about the same.
1. Set up the instrument at S1.
2. Set up the staff precisely vertically at point B; read off and record the height (backsight R).
3. Set up the staff at the turning point 1 (ground plate or prominent ground point); read off and record the height (foresight V).
4. Set up the instrument at S2 (the staff remains at the turning point 1).
5. Carefully rotate the staff at the turning point 1 so that it faces the instrument.
6. Read off the backsight and continue.
Staking out point heights
∆H = 1.00 metre below street level (Point A).
1.Set up the level so that the sighting distances to A and B are about the same. 2.Set up the staff at A and read off the backsight R = 1.305.
3.Set up the staff at B and read off the foresight V = 2.520. The difference h from the required height at B is calculated as: h = V – R - ∆H = 2.520 – 1.305 – 1.00 = +0.215m
4.Drive in a post at B and mark the required height (0.215m above ground level).
It is a simple but useful way to calculate the distance by using machines. By viewing this vlog one can easily learn the technique and calculation. Hope this can help you in your DIY to find the distance in your project.
Mr. Gautam Bhatia heads the Delhi based architecture firm that specialises in residences, institutions and luxury resorts. A recipient of several national and international awards, Mr. Bhatia fuses his training as a writer and his passion for arts with the architectural design. check out his work top Architecture Design
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