GSWA Widgiemooltha South 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 GSWA Widgiemooltha South TMI Grid Geodetic has a cell size of 0.00021 degrees (approximately 21m). The units are in nanoTesla (or nT). The data used to produce this grid was acquired in 2012 by the WA Government, and consisted of 131391 line-kilometres of data at 100m line spacing and 50m terrain clearance.总磁强度（Total Magnetic Intensity, TMI）数据用于衡量由地壳中成岩矿物成分差异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，其分类取决于岩石的磁化率。该数据已通过标准处理流程进行加工，以确保所记录的磁场响应仅源于地下岩石。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验，以确保GA发布的最终数据符合使用要求。本GSWA Widgiemooltha South TMI大地测量网格的单元格尺寸为0.00021度（约合21米），数据单位为纳特斯拉（nanoTesla, nT）。用于生成该网格的数据由西澳政府（WA Government）于2012年采集，总测线长度达131391线公里，测线间距为100米，地形离地高度为50米。