How to find the drawing number according to latitude and longitude?

You can consult books on cartography or surveying and mapping. The calculation is as follows:1:The map number of the 250,000 map is formed on the basis of 1: 1 10,000. According to the trapezoid framing, the latitude difference of 1: 1 million map is 6 degrees, and the latitude difference is 4 degrees. Then the coordinates you gave are the frame.

1:250,000 is divided into 16 pieces on the basis of 1: 1 10,000, that is, it is divided into/kloc-from left to right according to longitude difference 1.30 minutes and latitude difference 1.06 minutes.

1:50,000 is formed on the basis of 1: 1 10,000. Your coordinate number on 1: 18 is I-49- 1 18, which is on the map of 1:50000.

I-49- 188-B, the formula is too complicated to apply. Just find a tutorial on map framing on the internet and compare it.