改编自IGRF，能够计算全球地磁场的数值，课选择单点或者全球某个经纬范围内-Adapted from IGRF, be able to calculate the value of the global geomagnetic field, Lesson select a single point or a global latitude and longitude range withincu

计算地磁场场强，IGRF模型,可以批量生成地磁场数据，附带源码-IGRF model， Geomagnetic Field calculated at a point