This classification is based on a private-law statute of the VDP (Association of German Prädikat Wine Estates) and has no legislative function. Its declared aim is to restore the value of Germany's best sites (single vineyard sites), to ensure the preservation of a unique cultural landscape, to regain the status of great dry wines from Germany and to emphasise the importance of the tradition-rich fruit-sweet Prädikat wines. The statute defines the quality of a wine according to the internationally widely used term "terroir", i.e. origin in connection with quality. The principle applies that "the closer (smaller) the origin, the higher the quality". Vineyard quality is defined by the soil with topographical position and the prevailing climate or microclimate (see also under winegrowing worthiness).