What is the value of coefficient of refraction?

On the basis of reciprocal vertical angle measure- ments near Hannover (Germany), Carl Friedrich Gauss found an average value of the refraction coefficient k of approximately +0.13 [e.g., Brunner, 1984]. The Gaussian value of k is well known to the surveyor as a frequently used standard value of terrestrial refraction.

What is survey refraction?

refraction, terrestrial (angle of)— The angle of refraction, or the refraction, of a survey line is the angle at the point of observation between the true direction of the observed object and the direction as shown by light coming from it (direction of object as seen).

How do you calculate refraction correction?

Explanation: Combined correction for curvature and refraction is given by 0.06728 d2. Therefore, here, 0.06728(1.29)2 = 0.112 m. 9. In order to find the difference in elevation between two points P and Q, a level was set upon the line PQ, 30 m from P and 1280 m from Q.

What is curvature and refraction in surveying?

Due to curvature, the points appear to be lower than they actually are; while due to refraction, they appear to be higher than they actually are. …

How does wavelength affect refraction?

The amount of refraction increases as the wavelength of light decreases. Shorter wavelengths of light (violet and blue) are slowed more and consequently experience more bending than do the longer wavelengths (orange and red).

How does refraction affect surveying?

Levelling refraction refers to the systematic refraction effect distorting the results of line levelling over the Earth’s surface. In line levelling, short segments of a line are levelled by taking readings through a level from two staffs, one fore and one behind.

Where is data stored in total station?

Which unit in total station processes data collected? Explanation: Microprocessor is the unit that processes the data collected and uses it to compute various features like horizontal and vertical distances, slopes, elevation, etc. Explanation: Total station is affixed on to the tripod.

What is the rise and fall method?

Rise and fall is the method of surveying to solve the levelling to find out the difference in elevation and elevation of two points. In this method. Like we need to calculate the difference in elevation of the staff of two points.

Does index of refraction depend on wavelength?

The refractive index varies with wavelength linearly because different wavelengths interfere to different extents with the atoms of the medium. It is important to use monochromatic light to prevent dispersion of light into different colours.

What is the relation between lambda and frequency?

Frequency and wavelength are inversely proportional to each other. The wave with the greatest frequency has the shortest wavelength. Twice the frequency means one-half the wavelength.

What is the combined effect of curvature and refraction in survey?

Combined Effect of Curvature and Refraction in Survey. The combined effect of curvature and refraction is approximately. The formula for computing the combined effect of curvature and refraction is: C + R = 0.021K 2.

What is the refraction coefficient k?

The refraction coefficient k represents a common method for quantifying refraction in surveying measurements. It is defined as the ratio of the radius of the Earth R (spheroid) to the radius of the line of sight (e.g., [2, 3] ). The physical model of the refraction coefficient depends on the wavelength of light,…

How can the error due to curvature and refraction be eliminated?

The error due to curvature and refraction can be eliminated by equalising back sight and fore sight distances and also by the method of reciprocal levelling which is explained in the article.

What is the effect of refraction on a level rod?

The atmosphere refracts the horizontal line of sight downward, making the level rod reading smaller. The typical effect of refraction is equal to about 14% of the effect of earth curvature.