MRTAS SW Tasmania 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 MRTAS SW Tasmania tmi grid geodetic has a cell size of 0.00042 degrees (approximately 40m). The units are in nanoTesla (or nT). The data used to produce this grid was acquired in 2000 by the TAS Government, and consisted of 13701 line-kilometres of data at 200m line spacing and 80m 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。该数据集通过标准处理流程开展预处理，以确保所记录的磁场响应仅源于地下岩石。经处理后得到的数据集可通过地质解译揭示地下地质构造。经处理的数据由GA地球物理学家进行质量核验，以确保GA发布的最终数据符合使用需求。本次发布的塔斯马尼亚西南部MRTAS大地测量TMI网格数据集，其格网单元尺寸为0.00042度（约合40米），数据单位为纳特斯拉（nanoTesla，nT）。本网格数据集所用数据由塔斯马尼亚州政府于2000年采集，总测线长度达13701线公里，测线间距为200米，航空测量飞行离地高度为80米。