Geodesy and Celestial Mechanics

Latitude is defined as the angular distance of a point north or south of the equator, measured in degrees.

The coordinates 28 degrees 24 minutes 17 seconds N to 28 degrees 53 minutes 00 seconds N latitude and 76 degrees 50 minutes 24 seconds E to 77 degrees 20 minutes 37 seconds E longitude accurately define the geographical extent of Delhi.

The Earth is not a perfect sphere; due to its rotation, it bulges at the equator and is flattened at the poles, making its shape an oblate spheroid.

The average distance from the Earth to the Sun is approximately 149.6 million kilometers, which is commonly rounded to 150 million km.

This is the distance of the Moon from the Earth.

The 49th parallel north is the circle of latitude that forms the international boundary between the United States and Canada.

The Earth rotates 360 degrees in 24 hours. Therefore, 360/24 = 15 degrees per hour.

Fcentripetal = Fgravitation mω2R = mg or, ω = √ (g/R) or, T = 2π√(R/g) Since g = 9.8 m/s2 and r = R = 6.4×106 (radius of the earth) Now, T = 2π√(R/g) = 2π√ (6.4×106/9.8) = 84 min (approx.)  

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 In the idealized tricellular circulations, the sequence of pressure conditions from equator to poles is (i) Equatorial low, (ii) Subtropical high, (iii) Subpolar low, (iv) Polar high. The equatorial low pressure belt is located on either side of the geographical equator in a zone extending between 5°N and 5°S latitudes but this zone is not stationary because there is seasonal shift of belt. Subtropical high pressure belt extends between the latitude of 25°-35° in both the hemisphere. It is important to note that this high pressure belt is not thermally induced because this zone besides two to three winter months receives fairly high temperature throughout the year. Each polar low pressure belt is located between 60°- 65° latitudes in both the hemisphere. Polar high pressure belt persists at the poles throughout the year because of prevalence of very low temperature below freezing point all the year round.

For a closed traverse, the sum of latitudes and departures must be zero. By calculating the latitude (L = length * cos(azimuth)) and departure (D = length * sin(azimuth)) for each segment, one can solve for the missing length of PQ by setting the sum of all latitudes and departures to zero.

Geodetic surveying accounts for the curvature of the earth, whereas plane surveying assumes the earth is a flat surface. This is necessary for large-scale surveys.