A simple characterization method of the ordering of the nanopores is described for nanoporous anodized aluminium oxides. The method starts with image analysis on scanning electron microscopy representations for the purpose to find repetitive shapes and their centres, i.e. nanopores. Then triangles defined by coordinates of the centres are identified by Delaunay tessellation. Evaluation of the ordering degrees is then performed by a two-level analysis of the triangles. We define order parameters for triangular and hexagonal organization levels and show through typical examples that they are highly sensitive on ordering. (c) 2007 Elsevier B.V. All rights reserved.