All newly collected and relevant geophysical and lithological data from the Danish onshore area are continuously evaluated and examined in order to map and describe buried valleys.

A set of criterias has been developed to obtain a high degree of certainty and objectivity in the process of valley mapping. The most important criterion is that the lateral extent and the orientation of the valleys must be unambiguously expressed in the data. Therefore, no interpolations between the surveyed areas are made, and the map should therefore be considered a representation of the minimum occurrence of buried valleys.