Wellington 1 100k 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 Wellington 1 100k magnetic grid geodetic has a cell size of 0.00042 degrees (approximately 43m). The units are in nanoTesla (or nT). The data used to produce this grid was acquired in 1991 by the NSW Government, and consisted of 63636 line-kilometres of data at a line spacing between 200m and 400m, and 100m terrain clearance.

总磁强度（Total Magnetic Intensity, TMI）数据用于测量由地壳中成岩矿物含量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），具体取决于岩石的磁化率。本数据集采用标准流程开展预处理，确保记录的磁场响应仅由地下岩石引发。经处理得到的数据集可通过解译揭示地下地质构造。经预处理的数据将由GA的地球物理学家进行质量核查，以确保GA发布的最终数据符合使用要求。本惠灵顿1:10万磁测网格大地数据集的网格单元尺寸为0.00042度（约合43米），数据单位为纳特斯拉（nanoTesla，简称nT）。该网格数据由新南威尔士州（New South Wales, NSW）政府于1991年采集，原始数据总测线长度达63636公里，测线间距介于200米至400米之间，观测离地高度为100米。