GSSA Warrina TMI 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 Warrina TMI Grid Geodetic has a cell size of 0.00083 degrees (approximately 87m). The units are in nanoTesla (or nT). The data used to produce this grid was acquired in 2012 by the SA Government, and consisted of 132484 line-kilometres of data at 400m line spacing and 80m 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），其类型取决于岩石的磁化率特性。该数据集通过标准处理流程完成预处理，以确保记录的磁场响应仅由地下岩石产生。经处理得到的数据集可通过解译揭示地下地质构造。预处理后的数据由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需求。本次的GSSA Warrina TMI大地测量网格数据，其网格单元尺寸为0.00083度（约合87米），数据单位为纳特斯拉（nanoTesla，nT）。该网格的数据由南澳州政府（SA Government）于2012年采集，总测线长度达132484线千米，测线间距为400米，地形离地高度为80米。