Methods, apparatus and computer program code for terrain correction for geophysical surveys, in particular potential field surveys. A method of terrain correction for a geophysical survey involves capturing a multi- or hyperspectral image of a region to be surveyed; determining a surface geological composition of the surveyed region using the captured image multi- or hyperspectral image; determining terrain correction data for the geophysical survey using the determined surface geological composition; and using the terrain correction data for performing the terrain correction for the geophysical survey.