D-2 Surveying Flashcards
Level Transit
have full horizontal circle and partial vertical circle
vertical circle allows readings to and angle of 45 degrees
Transit
Transits have full horizontal and vertical circles., allowing full 360 degree reading. scales are equipped with and accurate vernier that can read to accuracy of one minute arc or less
Theodolite
have full horizontal and vertical circle. scale to measure angles uses a micro-adjustment technique that allows reading to be very accurate. up to one second of arc
Electronic Theodolite
have no scales to read at all. all angles displayed on LCD screen.
Level Transit (tool)
- used for both levelling and angle measurement.
- telescope level bubble and plate level bubble
- not popular due to inaccuracy
Open faced transit level
- called open face because horizontal and vertical circles are visible from the outside of the instrument.
- magnifying glass is needed to see fine graduations in vernier
- use horizontal and vertical circles to measure angles
Closed face transit level
- use vernier scale to read angle measurements
- eyepiece is used to read angle measurements
Electric Theodolite
- use LCD screen to display all angular measurements
- Horizontal angles in degrees minutes and seconds
- vertical angles in degrees minutes and seconds or percentage of slope
telescope eyepiece (transit)
eyepiece you look into. can be tuned clockwise and counter clockwise to focus crosshairs.
Telescope objective lens (transit)
opposite end from eye piece. main magnifying agent in telescope
Fisheye bubble(transit)
small level vial used to level instrument
Peep sight (transit)
small tube or markings on top of telescope used to roughly aim telescope at the target.
Telescope Level Vial (transit)
used to level telescope barrel accurately. must be perfectly level if transit is being used to level
Plate level vial (transit)
used to set plate level in all directions
Vertical circle Tangent screw(transit)
used for fine adjustment of telescope up or down.
Upper tangent screw(transit)
used to make the fine adjustment of telescope relative to horizontal circle. Locked by Upper clamp
Lower tangent screw(transit)
used to make fine adjustments to telescope relative to ground. Locked by Lower clamp
Horizontal circle(transit)
graduated protractor used to make horizontal angle measurements.
Vernier scale(transit)
Used to determine the circle readings to a finer degree then main circle.
Vertical circle (transit)
graduated ring used to measure vertical angles. only has one tangent crew and one clamp.
Horizontal Circle Eyepiece (transit)
used with closed faced transits to view horizontal circle
Horizontal circle illumination window(transit)
allows light into the interior of instrument so readings of horizontal circle can be made.
Vertical Circle eyepiece(transit)
allows readings to be taken on vertical circle. turning eyepiece will focus readings on graduation of vertical circle
Compass(transit)
Used to locate magnetic north. not used in building layout. used in property lines
magnetic declination
angle between true north and magnetic north.
Angle reading eyepiece (theo)
Allows operator to view horizontal and vertical circles to make readings. both made through same eyepiece
Light reflector(theo)
Small metal mirror that reflects light into the interior of instrument so readings can be taken
alidade clamp(theo)
Used to hold the theodolite to its base. purpose is to allow level to be removed easily without disrupting base.
Angle readings
Degrees , Minuets (‘) , seconds (“)
Electronic Distance Meter (EDM)
can accurately measure distances up to 7000 meters.
Sexagesimal system
using base of 60. system of angular measurements full circle divided into 360 degrees. each degree into 60 minutes each minute into 60 seconds
Supplementary angles
angles that add up to 180 degrees.
Complimentary angles
angles that add up to 90
Representing angles as Decimals
- Divide seconds by 60
- Add minutes and Divide by 60
- add the degrees.
eg 138° 20’ 11”
- 11/60 = 0.1833
- 0.1833 + 20 = 20.1833 / 60 = 0.3363
- 138.3363°
Converting from Decimals to DMS
- record whole degree
- multiply decimal portion by 60
- multiple decimal portion from step 2 by 60
Triangles
Sum of all three interior angles adds up to 180°
Right angle triangle
one interior angle is 90°
Pythagorean Teorem
A2 + B2 = C2
Trigonometry
deals with lengths of the sides and measurements of the angles that for a right triangle. expressed by three basic ratios “sine” , “Cosine” and “Tangent”
Calculating heights (transit)
vertical circle will read zero when telescope is set at level.
Zenith
vertical extension of plumb line of below the instrument to the top reading 0°0’0”
What is the difference between a Theodolite and a Transit?
A transit has vernier scales where as theodolites have a micro dial for more accurate readings
How many minutes are in each degree?
60
What is the difference between a Open faced Transit and a closed face transit?
an Open face Transit has the horizontal and vertical circles visible from the outside of the instrument where closed face has the circles internally
Which transit is used with a magnifying glass?
An open face Transit
What 2 ways can Vertical angles be displayed on a Electronic theodolite?
Degrees, Minutes, and seconds or in Percentage of slope. e.g., -2%
What is a Tangent Line?
A figurative line that is at a right angle to the radius of the circle. (where a Tangent Screw is located)
which Tangent screw adjusts the Vertical Circle?
Vertical Circle Tangent Screw
which Tangent screw adjusts the horizontal circle to the ground?
The lower Tangent Screw
which tangent screw adjusts the telescope relative to the horizontal circle?
The upper Tangent Screw
What do Tangent screws and plates get locked into position with?
Plate Clamps
What is used as a reference point for all angle readings on a vernier scale?
Zero
What is the main difference between the Vertical scale and horizontal scale?
The vertical Scale has only 1 tangent scale where as the horizontal has 2
What does it mean for a theodolite to have soft keys?
each botton to have more than one function
What does “Zenith” mean?
the point directly over the instrument
What function do you use if you have the opposite and adjacent sides?
Tangen
What does “Transiting the telescope” mean?
To flip the telescope 180 degrees and look in the opposite direction
What does the micro dial do?
repositions the horizontal and vertical circles. Should be set before the Theodolite is set to zero. adjusted to read the minutes and seconds on a theodolite
How much angular distance does each dot represent in the minutes and seconds window?
5” Seconds
What does Hz stand for?
Horizontal window icon
What does V stand for?
Vertical window icon
