1. Hainan plane coordinate system is a unified coordinate system for surveying and mapping Hainan Island and its adjacent waters. It is divided into three zones, and the central meridian and the prime meridian of each zone are different, and the error is also different.

2. Hainan Qiongzhong plane coordinate system is an independent coordinate system measured in Qiongzhong County and its surrounding areas. Its central meridian is110 e, and its initial meridian is11130' e, with an error of 0.5m ..

3. The conversion between Hainan plane coordinate system and Hainan Qiongzhong plane coordinate system requires conversion parameters, which can be inquired through surveying and mapping service agencies or online.