An evaluation of interpolation methods for Mars Orbiter Laser Altimeter (MOLA) data

The Mars Orbiter Laser Altimeter (MOLA) instrument on the Mars Global Surveyor (MGS) spacecraft has returned a large amount of data on the topography of Mars. It is possible to generate high resolution digital elevation models (DEMs) from these data by employing data interpolation techniques. Four interpolation algorithms were selected for testing on MOLA data: Delaunay-based linear interpolation, splining, nearest neighbour, and natural neighbour. These methods were applied to the MOLA data of Korolev crater for qualitative analysis. In addition, a DEM of a part of Iceland was used for quantitative testing by simulating MOLA data acquisition, interpolating those data, and then calculating the mean absolute error (MAE) between the interpolated and original DEM. Execution speeds were measured for the four algorithms. The natural neighbour method proved superior both quantitatively and qualitatively to other methods tested, but is relatively slow computationally.