GSSA Fowler TotalMagneticIntensity 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 GSSA Fowler TotalMagneticIntensity grid geodetic has a cell size of 0.00042 degrees (approximately 43m). The units are in nanoTesla (or nT). The data used to produce this grid was acquired in 2017 by the SA Government, and consisted of 94903 line-kilometres of data at 200m line spacing and 60m terrain clearance.

总磁强度（Total Magnetic Intensity, TMI）数据用于表征地壳中成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（磁场强度高于正常值）与负异常（磁场强度低于正常值）两类，其分类依据为岩石的磁化率。该数据已通过标准处理流程完成预处理，以确保所记录的磁场响应仅源自地下岩石的影响。经处理后得到的数据集可通过解译揭示地下地质构造特征。经处理后的数据已由GA地球物理学家完成质量核查，确保GA发布的最终数据符合使用需求。本GSSA Fowler总磁强度大地测量网格的单元格尺寸为0.00042度（约合43米）。数据单位为纳特斯拉（nanoTesla, nT）。用于生成该网格的数据由南澳大利亚州政府于2017年采集，总计94903测线公里，测线间距为200米，地形飞行离地高度为60米。