A line joining points on the Earth’s surface where the inclination of the geomagnetic field is zero. To avoid magnetic-anomaly distortions it is usually calculated from harmonics of the geomagnetic field less than 12.
科学参考收录了60776条科技类词条，基本涵盖了常见科技类参考文献及英语词汇的翻译，是科学学习和研究的有利工具。