Victoria River Downs 1 400, NT, 1998 (P1004), magnetic line data, AWAGS levelled

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. These line dataset from the Victoria River Downs, NT, 1998 survey were acquired in 1998 by the NT Government, and consisted of 90466 line-kilometres of data at 400m line spacing and 60m terrain clearance. To constrain long wavelengths in the data, an independent data set, the Australia-wide Airborne Geophysical Survey (AWAGS) airborne magnetic data, was used to control the base levels of the survey data. This survey data is essentially levelled to AWAGS.

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所引发的地球磁场强度变化。磁异常可分为正异常（磁场强度高于正常水平）与负异常（磁场强度低于正常水平），其分类取决于岩石的磁化率。该数据采用标准流程进行处理，以确保记录的磁场响应仅源自地下岩石。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。经处理的数据会由GA地球物理学家开展质量检查，以确保GA发布的最终数据满足应用需求。本次涉及的北领地（Northern Territory, NT）维多利亚河唐斯（Victoria River Downs）1998年勘测测线数据集，由北领地政府于1998年采集完成，总测线长度达90466测线公里，测线间距为400米，飞行离地高度为60米。为约束数据中的长波长分量，本次勘测采用了独立数据集——全澳航空地球物理调查（Australia-wide Airborne Geophysical Survey, AWAGS）航空磁测数据——对勘测数据的基准水平进行校准。本次勘测数据实质上已参照AWAGS数据完成了基准平差。