Lines of Equal Declination (Isogons)

The map service "Magnetic Variation Lines" offered for the technical information system "Geomagnetic Information" shows lines of the same declination (isogons) for most of Europe and adjacent areas. The isogons are based on the World Magnetic Model (WMM) and are calculated in advance for the current year. Land contours are not part of the service.面向“地磁信息”（Geomagnetic Information）技术信息系统提供的“磁变线”（Magnetic Variation Lines）地图服务，可展示欧洲绝大多数区域及邻近地带的同磁偏角等值线（等偏线，isogons）。该等偏线基于世界地磁模型（World Magnetic Model, WMM）构建，并已针对当前年份提前计算完毕。本服务未包含陆地轮廓线。