Summary of coordinates from BEIJING 54 to Xi'an 80

1. Beijing 54 and Xi'an 80 are two different kinds of ing planes with different reference elliptical bodies. Therefore, the coordinates of the same point are different under the two maps, The coordinates of the Three-degree belt and the Six-Degree belt are different from those of the longitude and latitude..
2. After digitization, the obtained coordinates are not actually the longitude and latitude coordinates of WGS84, because the conversion parameters of 54 and 80 have not been published so far, and there are no 54 or 80 projection series options in general software, WGS84 projection is often selected.
3. There is no ready-made formula BETWEEN WGS84, Beijing 54, and Xi'an 80.
4. For the 54 or 80 coordinates, the conversion from the latitude and longitude to the plane coordinates (three or six degree bands) can be completed through software.
5. The conversion between 54 and 80 must use the existing points and two kinds of coordinates to calculate the transformation parameters, and then convert the conversion coordinates. (Implemented by software)
6. When selecting a reference point, make sure that you do not select a river, contour line, place name, or height point. Do not select a highway as far as possible. These changes greatly on the two maps and cannot be used as a reference. Instead, you should choose fixed things, such as power stations and bridges.