1. A method for extracting a digital elevation model from a plurality of raw topographical points representing a plurality of frames, each frame representing a perspective of a multi-dimensional object comprising a surface and above-surface obstructions, the method comprising: finding the surface by filtering out data points representing the above-surface obstructions to provide a plurality of surface data points representing the surface; and filtering the surface data points with a competitive filter to provide a multi-dimensional surface shell of digital elevation model data points comprising a plurality of filtered frames.