GSWA South Pilbara 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 South Pilbara TMI Grid Geodetic has a cell size of 0.00083 degrees (approximately 89m). 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 134742 line-kilometres of data at 400m line spacing and 60m terrain clearance.总磁强度（Total Magnetic Intensity, TMI）数据用于表征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（磁场强度高于正常背景场）与负异常（磁场强度低于正常背景场），具体取决于岩石的磁化率。该数据通过标准化流程进行处理，以确保记录的响应仅源于地下岩石的影响。处理后得到的数据集可通过解译揭示地下地质结构。经处理的数据会由GA的地球物理学家开展质量校验，以确保GA发布的最终数据符合使用需求。本次的GSWA南皮尔巴拉TMI大地测量格网数据集，其格网单元尺寸为0.00083度（约89米），数据单位为纳特斯拉（nanoTesla, nT）。本格网的原始数据由西澳大利亚州政府于2012年采集，总测线长度达134742线公里，测线间距为400米，地形离地高度为60米。