GSV Alexandra VIMP Vic magnetic grid geodetic

Total magnetic intensity (TMI) data measures variations in the intensity of the Earth's magnetic field caused by the contrasting content of rock-forming minerals in the Earth crust. Magnetic anomalies can be either positive (field stronger than normal) or negative (field weaker) depending on the susceptibility of the rock. The data are processed via standard methods to ensure the response recorded is that due only to the rocks in the ground. The results produce datasets that can be interpreted to reveal the geological structure of the sub-surface. The processed data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose.This GSV Alexandra VIMP Vic magnetic grid geodetic has a cell size of 0.0005 degrees (approximately 50m). The units are in nanoTesla (or nT). The data used to produce this grid was acquired in 2000 by the VIC Government, and consisted of 23055 line-kilometres of data at 200m line spacing and 80m terrain clearance.

总磁场强度（Total Magnetic Intensity，TMI）数据用于衡量由地壳内造岩矿物成分差异所引发的地球磁场强度变化。磁异常可分为正异常（磁场强度高于正常背景值）与负异常（磁场强度低于正常背景值）两类，其类型取决于岩石的磁化率。该数据已通过标准处理流程进行校正，以确保记录的磁场响应仅源自地下岩石。经处理得到的数据集可通过解译揭示地下地质构造。经处理的数据已由GA地球物理学家开展质量核查，以确保GA发布的最终数据符合使用要求。本数据集为GSV Alexandra VIMP Vic测地地磁网格数据，其网格单元尺寸为0.0005度（约合50米），数据单位为纳特斯拉（nanoTesla，nT）。用于构建该网格的数据由维多利亚州（Victoria，VIC）政府于2000年采集，数据覆盖总长度达23055线公里，测线间距为200米，测线飞行时的地形离地高度为80米。