This could apply to point or raster values but imagine a raster of a continuous variable such as height (DTM). Is there a way to create a complete coverage of polygons that will have an equal area, taking into account the roughness of the underlying terrain? I realise that it would depend on where you seed the polygons (i.e. no unique solution) but if we accepted a certain degree of error it should be possible to do this with a nested regular grid (i.e. squares of differing fixed sizes)?