Survey reduction for glacier movement studies

Surveys of glaciers require special reduction techniques because of the continuous movement of ice. In the past, a minimum of two surveys of a network was needed to determine glacier velocities. A new approach is discussed in this paper. It uses conventional observation equations but allows station co-ordinates and observations to be time dependent. By selecting, a suitable network, a single adjustment of measurements made on different occasions can produce ice movement parameters even from a single survey.