The shoe size is converted into centimeter. Centimeter refers to the length of foot or shoe rt~

The shoe size is converted into centimeter. Centimeter refers to the length of foot or shoe rt~

It's the length inside the shoe
It's not the length of the sole
It's the length of the foot

What is the meaning of "three-dimensional zone projection" and "six dimensional zone projection" in Gaussian coordinate transformation? What is it for? How to use it?
Why are the x-axis coordinates of two GPS points with the same latitude transferred out by the "Gauss coordinate transformation" software different? Using "Gauss coordinate transformation" software to transform two GPS points of the same latitude, the x-axis coordinates are different. What's the matter? How to deal with it? For example, the coordinates of No.1 point n = 17 ° 00'00 ″ e = 36 ° 2'51 ″ are: x = 1880307.772, y = 12505058.077, the coordinates of No.2 point n = 17 ° 00'00 ″ e = 36 ° 37'00 ″ are x = 1880414.238, y = 12566850.555, and the two X-axis coordinates are 107 meters apart. What's the matter? The GPS I set is WGS84. Can you tell me what happened?

I feel a little sad to see many surveying and mapping Xiaobai ask this. I think if I am a professional, I will know if I listen carefully in the basic course of Surveying and mapping. If I am not a professional, I will know how to use software
This is an important problem of Surveying and mapping foundation. In order to avoid misunderstanding, we are now seeking materials in many ways. I summarize a Gaussian projection foundation, hoping to provide a correct reference for surveying and mapping practitioners
First of all, let's talk about what is Gauss projection? Then why to divide? How to divide? Then give some examples. I think it's good. I need to add some points
1. Gauss projection
Gauss projection, also known as transverse elliptical cylindrical equiangular projection, was first proposed by German surveyor Gauss in 1825-1830. In 1912, German surveyor Kruger derived a practical coordinate projection formula, also known as Gauss Kruger projection;
It belongs to orthomorphic projection, and its characteristic is that the central meridian does not deform. However, except for the central meridian, the lines of other meridian segments will deform after projection, and the farther the longitude is from the central meridian, the greater the deformation is
In order to control the length deformation after projection, we usually use the method of zonal projection. The zonation of 3-degree or 6-degree is commonly used, and the coordinate of city or engineering control network can be 1.5-degree or any zonation
2. 6 ° zone division:
Width of projection zone: divided by longitude difference between adjacent meridional planes
1) From the central meridian, every 6 ° from west to East, there are 60 zones in the world
2) The relationship between the band sign N and the longitude (L0) of its central meridian is as follows:
L0 = n×6°-3 °
3) If the longitude L is known, find the band number n:
n = int(L/6) + 1
4) There are 11 6 ° zones (13 to 23) in China
3. 3 ° zone:
1) It is divided into 120 zones every 3 ° from 1 ° 30 'E
2) The relationship between the band sign N and the longitude (L0) of its central meridian is as follows:
L0 =n×3°
3) If the longitude L is known, find the band number n:
n = int((L-1.5)/3) + 1
4) 21 3 ° zones (25 to 45 zones) in China
4. For example:
1) It is known that the longitude of a certain place is 117 degrees 32 minutes 36.456431 seconds (converted to 117.54346012 degrees first)
The corresponding band number of 6-degree band division is
N = int (117.54346012 ° / 6) + 1 = 20 band
The corresponding band number of 3-degree band division is
N = int (117.54346012 ° - 1.5 °) / 3) + 1 = 39 bands
2) If a certain area in China is divided into 20 zones, it is divided into 6 zones, in which the central meridian longitude is
L0=20*6°-3°=117°
If a certain area is 39 belt, it belongs to 3-degree belt, in which the central meridian longitude is
L0=39*3°=117°
5. This example has been verified. If your verification results are different, you are wrong. Please check the error carefully

For example, X: 4405456.05, Y: 13417559.166, H: 2824.429

First of all, the transformation of Gauss six degree belt coordinate to Gauss three degree belt coordinate is only related to plane coordinate, and has nothing to do with elevation. Secondly, you need to know which coordinate system the six degree belt coordinate is in. Here, suppose that in Xi'an 80 coordinate system, the first two digits of Y coordinate are 13, which means that the six degree belt number is 13, the central meridian is 75 ° and the conversion to longitude and latitude is b = 39

-1,1,3,5,7,9…… The general term formula of

an=2n－3