The reasons for the incorrect elevation of the result measured by Zhonghaida Max bathymeter are: incorrect datum setting, measurement error, data processing problems and complex terrain in the survey area.

1. Datum setting is incorrect: Please check whether you have selected the correct datum, such as geoid, mean sea level, etc. Choosing the correct datum is the premise to ensure the accuracy of elevation data.

2. Measurement error: The measurement error of the sounder may lead to inaccurate elevation data. You can reduce the error by averaging several measurements.

3. Data processing problem: There may be errors in the data processing process, resulting in incorrect elevation data. Please check whether there are any anomalies such as data loss and data confusion during data processing.

4. The terrain of the survey area is complex: If the terrain of the survey area is complex, such as steep mountains and canyons, the elevation data may be inaccurate. In this case, we can consider using other surveying methods, such as trigonometric leveling and satellite remote sensing.