OF TRIGONOMETRICAL SURVEYING

Excerpts

OF TRIGONOMETRICAL SURVEYING
In Geodesy, or the application of this part of Trigonometry to surveying, a line, called *the Base*, is measured between two convenient stations; and the angles between lines from these stations to points visible from the stations are measured with appropriate instruments.
OF TRIGONOMETRICAL SURVEYING
The horizontal angle between two objects is the angle between the vertical planes through the station and each object: it is also called the angle in azimuth.
OF TRIGONOMETRICAL SURVEYING
If the angle of elevation of $C$ be likewise measured at either station, the height of $C$ above that station can be found by solving a right-angled triangle of which the hypotenuse and one of the acute angles are known.
OF TRIGONOMETRICAL SURVEYING
For details of the measurement of a base, and a description of the instruments principally employed in practical surveying, the reader is referred to Professor Rankine’s *Manual of Civil Engineering*, Part 1.
OF TRIGONOMETRICAL SURVEYING
Where the extent of the earth’s surface surveyed is too great for the above supposition, the calculations have to be corrected for the sphericity of the earth (see books on Spherical Trigonometry), and in very great and very accurate surveys also for the earth’s deviation from a perfect sphere.

No exercises in this chapter.