For aesthetic reasons and ease of use, the map has been drawn up in a left-to-right orientation, rather than the more common north-south orientation. The overview map shows the distribution of the vineyards (in orange) across the territories of the three hill-based DOCs and highlights the most significant neighbouring features; in particular, the presence of the sea and the Alpine mountains. The graphic attention paid to the topography and the ‘green areas’ in which the vineyards are set helps to highlight the rich biodiversity of the wine-growing region in question, which has been remarkably preserved from monoculture.

The hills on which the three hilly DOCs are situated share a common geological history that, over time, gave rise to the Alps and Prealps. The hilly terrain consists of two different types of outcropping rock. At the centre of the map, the Vipacco Valley, which opens out onto the plains, marks the transverse fault line between the two types of rock. To the right are the limestone rocks of the Gorizia Karst and the Trieste Karst; to the left, the Flysch (locally known as Ponca) unites the soil types of the Collio and the Colli Orientali.