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The graduation on the horizontal scale are mark from 0° to _______
0°
90°
180°
360°
360°
In a transit theodolite, the horizontal circle is graduated from 0° to 360° in a clockwise direction · This circular scale allows for the precise measurement of horizontal angles between two points relative to a reference datum.
In a transit theodolite, the horizontal circle is graduated from 0° to 360° in a clockwise direction · This circular scale allows for the precise measurement of horizontal angles between two points relative to a reference datum.
H=VA−VB — where H is the horizontal angle, and V are the circle readings.
The horizontal circle consists of a graduated ring made of glass or metal · As the instrument's upper plate rotates about its vertical axis, the horizontal circle remains fixed relative to the leveling head, while the verniers or optical micrometers attached to the upper plate read the rotation against the 360° graduation.
The graduation is typically marked at intervals of 10' or 20' depending on the least count of the instrument.
Clockwise numbering is standard for direct horizontal angle measurements.
A full circle ensures that any angle in the horizontal plane can be measured without resetting the plate.
Allows for full 360-degree rotation
Continuous angular measurement capability
Susceptible to wear on the circular gear or graduation marks over time
Requires precise centering to avoid eccentricity errors
Traversing
Triangulation
Topographic surveying
The graduation of 0° to 360° is common for both transit theodolites and total stations.
Options A, B, and C are incorrect because they describe partial sectors which are insufficient for a complete horizontal circle in standard surveying.
D is correct — The horizontal circle of a standard theodolite is a complete 360° graduated scale.
Always ensure the 'Face Left' and 'Face Right' observations are taken to eliminate instrumental errors in horizontal angle measurements.