等偏角的线是一个恒定的磁偏角,*。*一条线的夹角地理北部和磁北是一些特定值。,(或等价于地理南亚&磁性)。你问的点在图中几个等偏角的满足。如果我们想象一个指南针和走动这样一个点,* *差地理南亚和磁场会迅速改变我们穿过许多不同等偏角的线,每个国家都有自己的赤纬。的一个点在地图上(右下)磁南极。如果我们想象走在一个圆这一点上,我们的指南针总是指向圆心,所以磁南会迅速改变。然而,地理南的方向将保持差不多只要我们走在不太大的一个圈。因此,此时的区别地理南亚和磁场变化迅速,因为南* *磁场的方向迅速改变。另一个点在地图上地理南极。 If we imagine walking in a circle about this point, our compass would always point pretty much in the same direction (towards the Magnetic South Pole.) However, the direction of geographic south would change rapidly as we walked around the south pole. Thus, at this point the difference between geographic south and magnetic south changes rapidly because the direction of *geographic south* changes rapidly. Note that [the same thing happens in the Arctic Ocean](https://maps.ngdc.noaa.gov/viewers/historical_declination/) as well. [![enter image description here][1]][1] [1]: https://i.stack.imgur.com/ZP4rZ.jpg