Aeroradiometric thorium map

Thorium map (cell size 50 m x 50 m) interpolated from aeroradiometric low flight data as a colour surface map. The data is based on low-flight measurements made by GTK throughout Finland, which were carried out in 1973-2007. The flight altitude was about 40 metres, the distance between the aerodromes was 200 metres, the flight lines travel from north to south or east to west based on the main geological direction, and the distance between the measuring points on the flight lines was about 50 metres.本数据集为基于航空放射性低空探测数据插值生成的栅格单元尺寸为50米×50米的钍元素含量彩色曲面分布图。数据源自芬兰地质调查局（GTK）于1973年至2007年间在芬兰全境开展的低空飞行探测工作。本次探测飞行高度约40米，起降机场间距为200米，测线依据区域主要地质走向布设为南北向或东西向，飞行线上的测点间距约50米。