GSNSW Grafton Tenterfield Thorium Grid Geodetic

The radiometric, or gamma-ray spectrometric method, measures the natural variations in the gamma-rays detected near the Earth's surface as the result of the natural radioactive decay of potassium (K), uranium (U) and thorium (Th). The data collected 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 radiometric thorium grid has a cell size of 0.0005 degrees (approximately 52m) and shows thorium element concentration of the Grafton - Tenterfield, NSW, 2011 in units of parts per million (or ppm). The data used to produce this grid was acquired in 2011 by the NSW Government, and consisted of 100488 line-kilometres of data at 250m line spacing and 60m terrain clearance.

辐射测量法（或称伽马射线光谱法，gamma-ray spectrometric method）通过检测地球表面附近因钾（K）、铀（U）和钍（Th）的自然放射性衰变产生的伽马射线自然变化进行测量。采集的数据经标准方法处理，确保记录的响应仅来源于地下岩石。处理结果生成的数据集可用于解析地下地质结构。GA的地球物理学家会对处理后的数据开展质量核查，以保证GA发布的最终数据符合预期用途。

该辐射测量钍网格的单元格大小为0.0005度（约52米），显示2011年澳大利亚新南威尔士州（NSW）格拉夫顿-滕特菲尔德地区的钍元素浓度，单位为百万分之一（ppm）。生成该网格的数据由新南威尔士州政府于2011年采集，涵盖100488线公里，线间距250米，地形净空高度60米。