Ê Ú ¼ ÂÙÐÝ ¾¼½½ ÔØ ½¿ ÇØÓ Ö ¾¼½½ ×ØÖ ØIn this article, we review special features of Gwyddiona modular, multiplatform, open-source software for scanning probe microscopy data processing, which is available at http://gwyddion.net/ . We describe its architecture with emphasis on modularity and easy integration of the provided algorithms into other software. Special functionalities, such as data processing from non-rectangular areas, grain and particle analysis, and metrology support are discussed as well. It is shown that on the basis of open-source software development, a fully functional software package can be created that covers the needs of a large part of the scanning probe microscopy user community.