What does cos mean in latitude and longitude

cos is a shorthand for cosine, a cosine function in mathematical trigonometry.

The earth is a standard sphere, the radius of the earth (that is, the radius of the equator) is r, the latitude of a certain latitude coil is , and the radius of this latitude coil is r, then r=rcos, then the circumference of the latitude coil of latitude is 2 r 2 rcos 40000cos (unit: km, because the circumference of the equator is 2 r 40000 km), then 40000 km 360 degrees km degrees, that is, the length of each longitude difference of the equator is about 111 km, then the latitude is The length of each longitude difference of the parallels is 40,000 cos, 360 degrees, and 111 cos kilometers.

Longitude is separated by one degree of length, and varies with the latitude of the location On the equator, the longitude of 360 degrees spans about 40,000 kilometers, so the distance spanned by 1 degree is kilometers.

But at the poles of the poles, the distance covered by 1 degree of longitude is only 0 degrees of latitude, but the distance between them is almost constant, and the distance spanned is one-third of a longitude coil, which is about 111 kilometers.

1 degree equals 60 minutes, and 1 minute equals 60 seconds.

In any place on the earth, as long as there is a watch, a bamboo pole, and a tape measure, you can know the local latitude and longitude. However, the table must be proofread against the country's standard time. Here's how:

1. Count two minutes first.

For example, in a certain place in China, the shortest time of the rod shadow is 13:20 at noon, and the ratio of the rod length to the shadow length is 1, then it can be seen that the place is 45° north latitude (tg = 1), and the ratio of the rod length to the shadow length at 100° east longitude (15° minus 1° in 1 hour and 1° in 4 minutes) needs to be found in the table, and a special angle is used here.

2. The algorithm for calculating the two solstices and longitude remains unchanged The latitude is in the northern hemisphere winter solstice +, and the summer solstice can be corrected by adding or subtracting the correction value on any day.

3. Correction value algorithm: that is, the difference in the number of days from two minutes or two solstices is multiplied by 94 365For example, on February 17, 2013, the difference between the vernal equinox on February 17, 2013 and March 22, 2013 is 33 days, that is, the direct point of the sun is in the southern latitude.

So the latitude obtained at noon today is (arctg+

tg = rod length shadow length.

The earth is a standard sphere, the radius of the earth (that is, the radius of the equator) is r, the latitude of a certain latitude coil is , and the radius of this latitude coil is r, then r=rcos, then the circumference of the latitude coil of latitude is 2 r 2 rcos 40000cos (unit: km, because the circumference of the equator is 2 r 40000 km), then 40000 km 360 degrees km degrees, that is, the length of each longitude difference of the equator is about 111 km, then the latitude is The length of each longitude difference of the parallels is 40,000 cos, 360 degrees, and 111 cos kilometers.

You look at it this way: make a perpendicular limb from a point on the weft coil (a) to the earth's axis (intersect with the earth's axis b) take the geocenter as o and make a line parallel to ab from the geocentric o towards the equator and intersect c with the equator c

Make a triangle. aob

You can see that ab is the radius of the latitude, and ao is the radius of the earth god.

The angular game collapse god AOC is the latitude angle.

ab=ao*cos（oab）

And the angle OAB = angle AOC (parallel lines.

The two inner angles are equal).

Now you see?