Hann River Walsh 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 Hann River Walsh magnetic grid geodetic has a cell size of 0.00083 degrees (approximately 91m). The units are in nanoTesla (or nT). The data used to produce this grid was acquired in 1991 by the QLD Government, and consisted of 61810 line-kilometres of data at 400m line spacing and 100m terrain clearance.总磁强度（Total Magnetic Intensity, TMI）数据用于测量由地壳内造岩矿物成分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开展处理，以确保记录的响应仅源自地下岩石。处理后得到的数据集可通过解译揭示地下地质构造。经处理的数据将由GA地球物理学家进行质量核验，确保GA发布的最终数据满足使用需求。本次汉恩河沃尔什（Hann River Walsh）磁测大地测量网格的格网单元尺寸为0.00083度（约91米），数据单位为纳特斯拉（nanoTesla, nT）。本网格所用数据由昆士兰州政府（QLD Government）于1991年采集，数据覆盖航带总长61810线千米，航带间距为400米，地形离地高度为100米。