1. A method for comparing a plurality of geometrical data representations each representing a spatial boundary surface of a corresponding geometrical object which surface changes over a selected extent of the object bounded thereby, the method comprising: providing the plurality of geometrical data representations on a common format basis, including scaling so as to each to have a common selected extent, to thereby result in a plurality of standardized spatial boundary surface geometrical data representations; selecting a plurality of section locations along each of the common extents of the standardized spatial boundary surface geometrical data representations so as to have the positions of the section locations along each common extent of a corresponding standardized spatial boundary surface geometrical data representation matched to those section locations along each of the remaining common extents of the other standardized spatial boundary surface geometrical data representations, providing a plurality of section outline curve representations for each of the plurality of standardized spatial boundary surface geometrical data representations about selected ones of the matched section locations; determining a pair of endpoints for each of the plurality of section outline curve representations at the selected ones of the matched section locations for each of the plurality of standardized spatial boundary surface geometrical data representations, and the chord length between each of the pairs of endpoints; scaling the section outline curve representations to each have a common chord length at a corresponding one of the selected matched section locations for each of the plurality of standardized spatial boundary surface geometrical data representations to form commonly scaled section outline curve representations for the corresponding one of the selected matched section locations from each of the plurality of standardized spatial boundary surface geometrical data representations; and comparing selected features of the commonly scaled section outline curve representations for the corresponding one of the selected matched section locations to provide a representation of an indication of similarity.