GSWA Holleton North 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 GSWA Holleton North magnetic grid geodetic has a cell size of 0.001 degrees (approximately 103m). The units are in nanoTesla (or nT). The data used to produce this grid was acquired in 1997 by the WA Government, and consisted of 4255 line-kilometres of data at 400m line spacing and 40m terrain clearance.

总磁强度（Total Magnetic Intensity, TMI）数据用于衡量由地壳中成岩矿物含量差异所引起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），具体取决于岩石的磁化率。该数据通过标准流程进行处理，以确保所记录的响应仅源自地下岩石。经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霍尔顿北磁网格大地测量数据集的格网单元尺寸为0.001度（约合103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大利亚政府于1997年采集，总测线长度达4255线公里，测线间距为400米，采集时的离地地形高度为40米。